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❓:An international development worker is designing a water distribution system for a rural village in West Africa. The village consists of 5 evenly spaced communities along a straight road of length ( L ) kilometers. Each community ( C_i ) (where ( i ) ranges from 1 to 5) has a specific water requirement ( W_i ) liters per day. The water source is located at one end of the road.1. Given that the cost to transport water is directly proportional to both the distance from the water source and the amount of water transported, formulate the total daily transportation cost ( T ) as a function of the distances ( d_i ) from the water source to each community and their respective water requirements.2. If the development worker decides to construct a secondary water reservoir at a point along the road to minimize the total transportation cost ( T ), determine the optimal location ( x ) (in kilometers from the water source) for the reservoir and the new total daily transportation cost. Assume that the cost per kilometer per liter of water transported is a constant ( k ).Note: Use advanced calculus and optimization techniques to solve this problem.
🧠:<think>Alright, so I'm trying to figure out how to help this international development worker design a water distribution system for a village in West Africa. The village has five communities along a straight road, each with their own water requirements. The water source is at one end, and we need to figure out the total transportation cost and then determine the best place to put a reservoir to minimize that cost.Starting with the first part: Formulating the total daily transportation cost T as a function of the distances d_i and water requirements W_i. The cost is directly proportional to both distance and the amount of water transported. So, if I think about it, for each community, the cost should be the distance from the source multiplied by the amount of water they need, and then multiplied by some constant of proportionality, which is given as k.So, for each community C_i, the cost would be k * d_i * W_i. Since there are five communities, the total cost T would be the sum of these individual costs. So, T = k * (d1*W1 + d2*W2 + d3*W3 + d4*W4 + d5*W5). That seems straightforward. I think that's the answer for part 1.Now, moving on to part 2. They want to construct a secondary reservoir somewhere along the road to minimize the total transportation cost. So, instead of transporting water directly from the source to each community, we can have water transported to the reservoir first, and then from the reservoir to each community. This might reduce the total cost because we can centralize the transportation.Let me visualize this. The road is a straight line of length L kilometers. The source is at one end, say point 0, and the communities are at positions d1, d2, d3, d4, d5 along this road. The reservoir will be placed at some point x between 0 and L. Then, water is transported from the source to the reservoir, and then from the reservoir to each community.So, the total transportation cost now has two components: the cost to transport water from the source to the reservoir, and then from the reservoir to each community. Let's break this down.First, the cost to transport water to the reservoir. The reservoir is at distance x from the source, so the cost to transport water to the reservoir is k * x * (total water needed). But wait, actually, each community's water is transported from the source to the reservoir, and then from the reservoir to the community. Hmm, maybe I need to think about it differently.Wait, no. If we have a reservoir at x, then water is transported from the source to the reservoir, and then from the reservoir to each community. So, the total amount of water transported from the source to the reservoir is the sum of all W_i, because all the water needed by the communities has to pass through the reservoir. Then, from the reservoir, each community gets its own W_i. So, the cost would be:Cost from source to reservoir: k * x * (W1 + W2 + W3 + W4 + W5)Plus, the cost from reservoir to each community: for each community, if it's beyond the reservoir, the distance is (d_i - x), and if it's before the reservoir, the distance is (x - d_i). But wait, actually, since the reservoir is somewhere along the road, some communities are closer to the source than the reservoir, and some are farther. So, for communities before the reservoir (d_i < x), the distance from the reservoir is (x - d_i), and for those after (d_i > x), it's (d_i - x). But since the reservoir is at x, all communities beyond x will have their water transported from the reservoir, which is closer than the source.Wait, actually, no. The water is transported from the source to the reservoir, and then from the reservoir to each community. So, for each community, the total distance the water travels is x (from source to reservoir) plus |d_i - x| (from reservoir to community). So, the total distance per liter for each community is x + |d_i - x|. Therefore, the total cost for each community is k * (x + |d_i - x|) * W_i.Therefore, the total cost T is the sum over all communities of k*(x + |d_i - x|)*W_i. So, T = k * sum_{i=1 to 5} (x + |d_i - x|) * W_i.Simplifying that, T = k * [sum_{i=1 to 5} x*W_i + sum_{i=1 to 5} |d_i - x|*W_i] = k * [x * sum W_i + sum |d_i - x| * W_i].But since sum W_i is a constant, let's denote S = W1 + W2 + W3 + W4 + W5. So, T = k * [x*S + sum_{i=1 to 5} |d_i - x|*W_i].Wait, but actually, the first term is x*S, which is the cost to transport all the water to the reservoir, and then the second term is the cost to transport from the reservoir to each community. So, that makes sense.Now, to minimize T with respect to x, we need to find the x that minimizes T. Since k is a positive constant, we can ignore it for the purpose of minimization and focus on minimizing the expression inside the brackets: f(x) = x*S + sum |d_i - x|*W_i.So, f(x) = x*S + sum_{i=1 to 5} |d_i - x|*W_i.We need to find the x that minimizes f(x). To do this, we can consider the derivative of f(x) with respect to x and set it to zero.But since f(x) involves absolute values, the function is piecewise linear, and the minimum occurs where the derivative changes sign from negative to positive. The derivative of |d_i - x| with respect to x is -1 if x < d_i and +1 if x > d_i. At x = d_i, the derivative is undefined, but we can consider it as a point where the slope changes.Therefore, the derivative of f(x) is:f'(x) = S + sum_{i=1 to 5} W_i * d/dx |d_i - x|Which is:f'(x) = S + sum_{i=1 to 5} W_i * (-sign(d_i - x))Where sign(d_i - x) is -1 if x < d_i, +1 if x > d_i, and undefined at x = d_i.So, f'(x) = S - sum_{i=1 to 5} W_i * sign(d_i - x)We need to find x where f'(x) = 0.So, S - sum_{i=1 to 5} W_i * sign(d_i - x) = 0Which implies sum_{i=1 to 5} W_i * sign(d_i - x) = SNow, sign(d_i - x) is -1 if x > d_i, +1 if x < d_i, and 0 if x = d_i. Wait, actually, no. If x < d_i, then d_i - x > 0, so sign is +1. If x > d_i, then d_i - x < 0, so sign is -1. If x = d_i, sign is 0.Therefore, sum_{i=1 to 5} W_i * sign(d_i - x) = sum_{i: x < d_i} W_i - sum_{i: x > d_i} W_iBecause for x < d_i, sign is +1, so we add W_i, and for x > d_i, sign is -1, so we subtract W_i.So, the equation becomes:sum_{i: x < d_i} W_i - sum_{i: x > d_i} W_i = SBut S is the total sum of W_i, so S = sum_{i=1 to 5} W_i.Therefore, sum_{i: x < d_i} W_i - sum_{i: x > d_i} W_i = sum_{i=1 to 5} W_iLet me rearrange this:sum_{i: x < d_i} W_i = sum_{i: x > d_i} W_i + sum_{i=1 to 5} W_iWait, that doesn't seem right. Let's double-check.Wait, the equation is:sum_{i: x < d_i} W_i - sum_{i: x > d_i} W_i = SBut S is sum_{i=1 to 5} W_i, so:sum_{i: x < d_i} W_i - sum_{i: x > d_i} W_i = sum_{i=1 to 5} W_iLet me denote A = sum_{i: x < d_i} W_i and B = sum_{i: x > d_i} W_i. Then, the equation is A - B = A + B, because S = A + B.Wait, that can't be. Let me see:Wait, no. If A = sum_{i: x < d_i} W_i and B = sum_{i: x > d_i} W_i, then the equation is A - B = S.But S = A + B + C, where C is the sum of W_i for i where x = d_i. But in our case, x is not necessarily one of the d_i, so C = 0. Therefore, S = A + B.So, the equation becomes A - B = A + BSubtracting A from both sides: -B = B => -B = B => 2B = 0 => B = 0.But B is the sum of W_i for i where x > d_i. So, B = 0 implies that there are no communities beyond x, meaning x is beyond all d_i. But that can't be, because x is somewhere along the road, and the communities are spread out.Wait, this suggests that my approach might be flawed. Maybe I made a mistake in setting up the derivative.Let me go back. The total cost is f(x) = x*S + sum |d_i - x|*W_i.To find the minimum, we can consider the derivative. However, because of the absolute values, the function is not differentiable at the d_i points, but we can consider the slope changes.The derivative of f(x) is S + sum_{i=1 to 5} W_i * d/dx |d_i - x|.As I mentioned earlier, d/dx |d_i - x| is -1 if x < d_i, +1 if x > d_i, and undefined at x = d_i.So, f'(x) = S - sum_{i=1 to 5} W_i * sign(d_i - x)Wait, but sign(d_i - x) is +1 if x < d_i, -1 if x > d_i.Therefore, f'(x) = S - [sum_{i: x < d_i} W_i - sum_{i: x > d_i} W_i]Because for x < d_i, sign is +1, so we have -W_i, and for x > d_i, sign is -1, so we have +W_i.So, f'(x) = S - [sum_{i: x < d_i} W_i - sum_{i: x > d_i} W_i]We set this equal to zero:S - [sum_{i: x < d_i} W_i - sum_{i: x > d_i} W_i] = 0Which implies:sum_{i: x < d_i} W_i - sum_{i: x > d_i} W_i = SBut S is the total sum, so:sum_{i: x < d_i} W_i - sum_{i: x > d_i} W_i = sum_{i=1 to 5} W_iLet me denote A = sum_{i: x < d_i} W_i and B = sum_{i: x > d_i} W_i. Then, the equation is:A - B = A + BSubtracting A from both sides:-B = B => -2B = 0 => B = 0Which means sum_{i: x > d_i} W_i = 0, implying that there are no communities beyond x. But that would mean x is beyond all d_i, which is at position L. But if x = L, then the reservoir is at the farthest point, which might not be optimal.Wait, this suggests that the minimum occurs at x = L, but that doesn't make sense because transporting water all the way to L and then back to the communities might not be optimal.I think I made a mistake in the derivative setup. Let me reconsider.The total cost is f(x) = x*S + sum |d_i - x|*W_i.But actually, when we have a reservoir at x, the water is transported from the source to x, and then from x to each community. So, for each community, the total distance is x + |d_i - x|, as I thought earlier.But wait, if x is between 0 and d_i, then |d_i - x| = d_i - x, so total distance is x + (d_i - x) = d_i. So, the total distance is just d_i, same as before. But that can't be right because then the reservoir doesn't help.Wait, no. If x is between 0 and d_i, then the water is transported from source to x, then from x to d_i, so total distance is x + (d_i - x) = d_i. So, the total cost for that community is k*d_i*W_i, same as before. But if x is beyond d_i, then the water is transported from source to x, then from x back to d_i, so total distance is x + (x - d_i) = 2x - d_i. So, the cost is k*(2x - d_i)*W_i.Wait, that makes sense. So, for communities before x, the cost is k*(2x - d_i)*W_i, and for communities after x, the cost is k*d_i*W_i.Wait, no, actually, if x is beyond d_i, then the water is transported from source to x, then from x back to d_i, which is a distance of x - d_i. So, total distance is x + (x - d_i) = 2x - d_i.But if x is before d_i, then the water is transported from source to x, then from x to d_i, which is d_i - x. So, total distance is x + (d_i - x) = d_i.Therefore, for each community, the total distance is:- If x <= d_i: d_i- If x > d_i: 2x - d_iTherefore, the total cost is:T = k * [sum_{i: x <= d_i} d_i*W_i + sum_{i: x > d_i} (2x - d_i)*W_i]So, T = k * [sum_{i=1 to 5} d_i*W_i - sum_{i: x > d_i} d_i*W_i + 2x*sum_{i: x > d_i} W_i]Because for x > d_i, we replace d_i with (2x - d_i), so the change is +2x*W_i - d_i*W_i.Therefore, T = k * [sum d_i*W_i + 2x*sum_{i: x > d_i} W_i - sum_{i: x > d_i} d_i*W_i]Let me denote:- Let A = sum_{i: x > d_i} W_i- Let B = sum_{i: x > d_i} d_i*W_iThen, T = k * [sum d_i*W_i + 2x*A - B]To minimize T with respect to x, we can take the derivative of T with respect to x and set it to zero.But T is a linear function in x for regions between the d_i points. The minimum occurs where the slope changes from negative to positive.The slope of T with respect to x is dT/dx = k * [2A]So, dT/dx = 2k*AWait, but A is the sum of W_i for communities beyond x. As x increases, A decreases because more communities are no longer beyond x.Wait, actually, the slope is 2k*A, which is positive if A > 0. So, as x increases, T increases if A > 0, and decreases if A < 0. But A is always non-negative because it's a sum of weights.Wait, this suggests that T is increasing with x, which can't be right because if x is too large, the cost would increase. But if x is too small, the cost might also increase.Wait, perhaps I need to reconsider. Let me think about the derivative more carefully.Actually, T is a piecewise linear function, and the slope changes at each d_i. The slope in each interval between d_i and d_{i+1} is 2k*A, where A is the sum of W_i for communities beyond x.So, as x increases, A decreases because more communities are no longer beyond x. Therefore, the slope decreases as x increases.We need to find the x where the slope changes from negative to positive. Wait, but if the slope is 2k*A, and A is positive, then the slope is always positive, meaning T is increasing with x. That would suggest that the minimum occurs at the smallest possible x, which is x=0, but that contradicts intuition because placing the reservoir at x=0 would mean no reservoir, just transporting directly, which might not be optimal.Wait, I must be making a mistake here. Let me go back.The total cost is T = k * [sum d_i*W_i + 2x*A - B], where A = sum_{i: x > d_i} W_i and B = sum_{i: x > d_i} d_i*W_i.So, the derivative of T with respect to x is dT/dx = k * [2A]But A is the sum of W_i for i where x > d_i. So, as x increases, A decreases because some W_i are subtracted from A as x crosses their d_i.Therefore, dT/dx = 2k*A. So, when A > 0, dT/dx > 0, meaning T is increasing with x. When A = 0, dT/dx = 0, meaning T is minimized at the point where A = 0, which is x = L, the farthest point.But that can't be right because placing the reservoir at L would mean transporting all water to L and then back to each community, which would be more expensive than transporting directly.Wait, perhaps I'm misunderstanding the problem. Maybe the reservoir is used to store water, so water is transported from the source to the reservoir, and then distributed from there. So, the total cost is the cost to transport all water to the reservoir plus the cost to distribute from the reservoir to each community.So, the cost to transport to the reservoir is k*x*S, where S is the total water needed.Then, the cost to distribute from the reservoir is k*sum |d_i - x|*W_i.Therefore, total cost T = k*x*S + k*sum |d_i - x|*W_i.So, T = k*(x*S + sum |d_i - x|*W_i)Now, to minimize T, we can ignore the constant k and focus on minimizing f(x) = x*S + sum |d_i - x|*W_i.Now, the derivative of f(x) is f'(x) = S + sum_{i=1 to 5} W_i * d/dx |d_i - x|As before, d/dx |d_i - x| is -1 if x < d_i, +1 if x > d_i, and undefined at x = d_i.Therefore, f'(x) = S - sum_{i=1 to 5} W_i * sign(d_i - x)Wait, no. Because d/dx |d_i - x| is -1 if x < d_i, +1 if x > d_i.So, f'(x) = S + sum_{i=1 to 5} W_i * (-sign(d_i - x))Which is f'(x) = S - sum_{i=1 to 5} W_i * sign(d_i - x)We set f'(x) = 0:S - sum_{i=1 to 5} W_i * sign(d_i - x) = 0Which implies sum_{i=1 to 5} W_i * sign(d_i - x) = SNow, sign(d_i - x) is +1 if x < d_i, -1 if x > d_i, and 0 if x = d_i.So, sum_{i=1 to 5} W_i * sign(d_i - x) = sum_{i: x < d_i} W_i - sum_{i: x > d_i} W_iTherefore, the equation becomes:sum_{i: x < d_i} W_i - sum_{i: x > d_i} W_i = SBut S is the total sum of W_i, so:sum_{i: x < d_i} W_i - sum_{i: x > d_i} W_i = sum_{i=1 to 5} W_iLet me denote A = sum_{i: x < d_i} W_i and B = sum_{i: x > d_i} W_i. Then, the equation is:A - B = A + BSubtracting A from both sides:-B = B => -2B = 0 => B = 0Which implies that sum_{i: x > d_i} W_i = 0, meaning there are no communities beyond x. Therefore, x must be greater than or equal to all d_i, which is x = L.But that can't be right because placing the reservoir at L would mean transporting all water to L and then distributing it back, which would be more expensive than not having a reservoir at all.Wait, this suggests that the minimum occurs at x = L, but that doesn't make sense. Maybe I made a mistake in the derivative.Alternatively, perhaps the optimal x is the weighted median of the d_i with weights W_i.Wait, in optimization problems involving absolute deviations, the minimum is achieved at the median. In this case, since we have weights, it's the weighted median.So, the optimal x is the point where the cumulative weight from the left is just less than or equal to half of the total weight, and the cumulative weight from the right is just greater than or equal to half.Let me think about that.The weighted median is the point x such that the sum of weights for d_i <= x is at least half of the total weight, and the sum of weights for d_i >= x is also at least half.So, to find x, we need to order the communities by their distances d_i, and find the x where the cumulative weight from the left is >= S/2 and the cumulative weight from the right is >= S/2.Wait, but in our case, the derivative condition led us to x = L, which suggests that the weighted median is at L, which might be the case if the weights are such that the cumulative weight from the left never reaches S/2 before L.Alternatively, perhaps I need to consider the derivative correctly.Wait, let's go back to f'(x) = S - [sum_{i: x < d_i} W_i - sum_{i: x > d_i} W_i]We set f'(x) = 0:S = sum_{i: x < d_i} W_i - sum_{i: x > d_i} W_iBut S is the total sum, so:sum_{i: x < d_i} W_i - sum_{i: x > d_i} W_i = sum_{i=1 to 5} W_iLet me rearrange:sum_{i: x < d_i} W_i = sum_{i: x > d_i} W_i + sum_{i=1 to 5} W_iBut sum_{i: x > d_i} W_i + sum_{i=1 to 5} W_i = sum_{i: x > d_i} W_i + sum_{i: x <= d_i} W_i + sum_{i: x > d_i} W_iWait, that can't be. Let me think again.Wait, no. sum_{i: x < d_i} W_i + sum_{i: x > d_i} W_i + sum_{i: x = d_i} W_i = SBut in our equation, we have sum_{i: x < d_i} W_i = sum_{i: x > d_i} W_i + SWhich implies:sum_{i: x < d_i} W_i - sum_{i: x > d_i} W_i = SBut sum_{i: x < d_i} W_i - sum_{i: x > d_i} W_i = SBut sum_{i: x < d_i} W_i + sum_{i: x > d_i} W_i = S - sum_{i: x = d_i} W_iWait, this is getting too convoluted. Maybe I should approach it differently.Let me consider the derivative f'(x) = S - [sum_{i: x < d_i} W_i - sum_{i: x > d_i} W_i]We can write this as f'(x) = S - sum_{i: x < d_i} W_i + sum_{i: x > d_i} W_iBecause subtracting a negative is adding.So, f'(x) = S - sum_{i: x < d_i} W_i + sum_{i: x > d_i} W_iBut S = sum_{i=1 to 5} W_i, so:f'(x) = sum_{i=1 to 5} W_i - sum_{i: x < d_i} W_i + sum_{i: x > d_i} W_iSimplify:f'(x) = sum_{i: x >= d_i} W_i + sum_{i: x > d_i} W_iWait, no. Let me see:sum_{i=1 to 5} W_i - sum_{i: x < d_i} W_i = sum_{i: x >= d_i} W_iAnd then + sum_{i: x > d_i} W_iSo, f'(x) = sum_{i: x >= d_i} W_i + sum_{i: x > d_i} W_iWait, that doesn't seem right. Maybe I need to think of it as:f'(x) = S - sum_{i: x < d_i} W_i + sum_{i: x > d_i} W_iBut S = sum_{i: x < d_i} W_i + sum_{i: x >= d_i} W_iSo, substituting S:f'(x) = [sum_{i: x < d_i} W_i + sum_{i: x >= d_i} W_i] - sum_{i: x < d_i} W_i + sum_{i: x > d_i} W_iSimplify:f'(x) = sum_{i: x >= d_i} W_i + sum_{i: x > d_i} W_iWait, that still doesn't make sense. I think I'm overcomplicating this.Let me try a different approach. Let's order the communities by their distances d_i. Let's say d1 < d2 < d3 < d4 < d5.We need to find x such that the derivative changes from negative to positive. The derivative f'(x) is S - [sum_{i: x < d_i} W_i - sum_{i: x > d_i} W_i]We can write this as f'(x) = S - sum_{i: x < d_i} W_i + sum_{i: x > d_i} W_iWe need to find x where f'(x) = 0.So, S - sum_{i: x < d_i} W_i + sum_{i: x > d_i} W_i = 0Which implies:sum_{i: x < d_i} W_i = S + sum_{i: x > d_i} W_iBut sum_{i: x < d_i} W_i + sum_{i: x > d_i} W_i = S - sum_{i: x = d_i} W_iSo, substituting:sum_{i: x < d_i} W_i = S + (S - sum_{i: x < d_i} W_i - sum_{i: x = d_i} W_i)Simplify:sum_{i: x < d_i} W_i = 2S - sum_{i: x < d_i} W_i - sum_{i: x = d_i} W_iBring terms to one side:2*sum_{i: x < d_i} W_i + sum_{i: x = d_i} W_i = 2SDivide both sides by 2:sum_{i: x < d_i} W_i + (1/2)*sum_{i: x = d_i} W_i = SThis suggests that the optimal x is the point where the cumulative weight from the left plus half the weight at x equals S/2.Wait, that sounds like the weighted median. The weighted median is the point where the cumulative weight from the left is at least S/2 and the cumulative weight from the right is at least S/2.So, to find x, we need to order the communities by d_i, compute the cumulative sum of W_i, and find the smallest x where the cumulative sum is >= S/2.Let me try an example. Suppose we have communities at positions d1=1, d2=2, d3=3, d4=4, d5=5, with weights W1=1, W2=2, W3=3, W4=4, W5=5. Total S=15, so S/2=7.5.Cumulative sum from left:d1: 1 (sum=1)d2: 2 (sum=3)d3: 3 (sum=6)d4: 4 (sum=10)At d4, the cumulative sum reaches 10, which is >=7.5. So, the weighted median is at d4=4.But in our case, the derivative condition led us to x= L, which might not be the case. Maybe the weighted median is the correct approach.So, in general, the optimal x is the weighted median of the d_i with weights W_i.Therefore, to find x, we need to:1. Order the communities by their distances d_i.2. Compute the cumulative sum of W_i as we move from left to right.3. The optimal x is the smallest d_i where the cumulative sum is >= S/2.If the cumulative sum at a certain d_i is exactly S/2, then x can be anywhere between that d_i and the next one. If it's not exact, x is at the d_i where the cumulative sum first exceeds S/2.So, applying this to the problem, the optimal x is the weighted median of the d_i with weights W_i.Once x is determined, the total cost T can be calculated as:T = k*(x*S + sum |d_i - x|*W_i)But since x is the weighted median, we can compute the sum |d_i - x|*W_i.Alternatively, since x is the weighted median, the derivative condition is satisfied, so f'(x)=0, which gives us the minimal cost.Therefore, the optimal location x is the weighted median of the d_i with weights W_i, and the new total daily transportation cost is T = k*(x*S + sum |d_i - x|*W_i).But to express this more concretely, we need to know the specific d_i and W_i values. Since they are not provided, we can only express the answer in terms of the weighted median.So, in conclusion, the optimal x is the weighted median of the communities' distances, and the total cost is calculated accordingly.</think>
❓:During the Second World War, a secret espionage network used a pattern of monuments as a covert method to transmit encrypted messages. These monuments are positioned in a specific region and form a network that can be modeled mathematically.1. The coordinates of five key monuments (A, B, C, D, E) in the network are given as follows: - A: (2, 3) - B: (5, 7) - C: (11, 13) - D: (17, 19) - E: (23, 29) The encrypted message is hidden in the area of the pentagon formed by these five monuments. Calculate the exact area of the pentagon using the given coordinates.2. To decode the message, an art historian discovers that the network also follows a specific transformation rule. Each monument’s coordinates (x, y) are transformed to new coordinates (X, Y) using the following linear transformations: [ X = ax + by ] [ Y = cx + dy ] where (a, b, c, d) are constants that must be determined. The transformed coordinates of the monument A (2, 3) are known to be (19, 25), and the transformed coordinates of the monument B (5, 7) are known to be (47, 61). Determine the constants (a, b, c,) and (d).Combine your results to provide insights into the historical context and significance of these espionage-related monuments.
🧠:<think>Alright, so I have this problem about calculating the area of a pentagon formed by five monuments and then figuring out a linear transformation that maps their coordinates. Hmm, okay. Let me take it step by step.First, part 1 is about finding the area of the pentagon with given coordinates. The coordinates are:- A: (2, 3)- B: (5, 7)- C: (11, 13)- D: (17, 19)- E: (23, 29)I remember there's a formula for the area of a polygon when you have the coordinates of its vertices. It's called the shoelace formula, right? Yeah, that's the one. The formula is something like half the absolute difference between the sum of the products of the coordinates going one way and the sum going the other way.Let me write that down. For a polygon with vertices (x1, y1), (x2, y2), ..., (xn, yn), the area is:Area = (1/2) * |(x1y2 + x2y3 + ... + xn y1) - (y1x2 + y2x3 + ... + ynx1)|So, I need to apply this to the pentagon A, B, C, D, E.First, I should list the coordinates in order, either clockwise or counterclockwise. The problem says it's a pentagon formed by these five monuments, so I assume they are given in order. Let me check the coordinates:A: (2,3), B: (5,7), C: (11,13), D: (17,19), E: (23,29)Looking at the x and y coordinates, each subsequent point seems to have higher x and y values. So, it's likely that they are in order, either clockwise or counterclockwise. Let me visualize this.Plotting the points roughly:A is at (2,3), which is lower left.B is at (5,7), moving up and right.C is at (11,13), further up and right.D is at (17,19), even more.E is at (23,29), the farthest.So, connecting A to B to C to D to E and back to A would form a convex pentagon. So, the shoelace formula should work here.Let me set up the coordinates in order and repeat the first point at the end to close the polygon.So, the points are:1. A: (2,3)2. B: (5,7)3. C: (11,13)4. D: (17,19)5. E: (23,29)6. A: (2,3)Now, I need to compute two sums:Sum1 = (x1y2 + x2y3 + x3y4 + x4y5 + x5y6)Sum2 = (y1x2 + y2x3 + y3x4 + y4x5 + y5x6)Then, Area = (1/2)|Sum1 - Sum2|Let me compute Sum1 first.Compute each term:x1y2 = 2*7 = 14x2y3 = 5*13 = 65x3y4 = 11*19 = 209x4y5 = 17*29 = 493x5y6 = 23*3 = 69Sum1 = 14 + 65 + 209 + 493 + 69Let me add these up step by step:14 + 65 = 7979 + 209 = 288288 + 493 = 781781 + 69 = 850So, Sum1 = 850Now, Sum2:y1x2 = 3*5 = 15y2x3 = 7*11 = 77y3x4 = 13*17 = 221y4x5 = 19*23 = 437y5x6 = 29*2 = 58Sum2 = 15 + 77 + 221 + 437 + 58Adding these up:15 + 77 = 9292 + 221 = 313313 + 437 = 750750 + 58 = 808So, Sum2 = 808Now, compute the difference: Sum1 - Sum2 = 850 - 808 = 42Take the absolute value, which is still 42.Then, Area = (1/2)*42 = 21Wait, that seems too small. Is that correct? Let me double-check my calculations.First, Sum1:2*7 = 145*13 = 6511*19 = 20917*29 = 49323*3 = 69Adding: 14 + 65 = 79; 79 + 209 = 288; 288 + 493 = 781; 781 + 69 = 850. That seems correct.Sum2:3*5 = 157*11 = 7713*17 = 22119*23 = 43729*2 = 58Adding: 15 + 77 = 92; 92 + 221 = 313; 313 + 437 = 750; 750 + 58 = 808. That also seems correct.Difference: 850 - 808 = 42. Half of that is 21. Hmm, okay. So the area is 21 square units.Wait, but looking at the coordinates, these points are spread out quite a bit. From (2,3) to (23,29), that's a span of 21 in x and 26 in y. So, a pentagon covering that area having an area of 21 seems small. Maybe I made a mistake in the order of the points?Wait, the shoelace formula requires the points to be ordered either clockwise or counterclockwise without crossing. Maybe I assumed the wrong order? Let me check if the points are indeed in order.Looking at the coordinates:A: (2,3)B: (5,7) – moving right and upC: (11,13) – further right and upD: (17,19) – same directionE: (23,29) – sameSo, connecting A-B-C-D-E-A should form a convex pentagon. So, the order is correct.Alternatively, maybe I missed a point? No, the shoelace formula was applied correctly with five points and back to the first.Wait, another thought: perhaps the area is indeed 21 because the points are colinear in some way? Let me check if the points lie on a straight line or something.Looking at the coordinates:A: (2,3)B: (5,7)C: (11,13)D: (17,19)E: (23,29)Wait a second, these points seem to follow a pattern. Let me see:From A to B: x increases by 3, y increases by 4.From B to C: x increases by 6, y increases by 6.From C to D: x increases by 6, y increases by 6.From D to E: x increases by 6, y increases by 10.Wait, so the increments aren't consistent. So, not a straight line.But looking at the coordinates, maybe they lie on a parabola or something? Let me see.Looking at the x and y coordinates:x: 2, 5, 11, 17, 23y: 3, 7, 13, 19, 29Looking at the differences:For x:5-2=311-5=617-11=623-17=6So, x increments: 3,6,6,6For y:7-3=413-7=619-13=629-19=10So, y increments: 4,6,6,10Not a linear pattern, but maybe quadratic?Let me see if y is a quadratic function of x.Assume y = ax² + bx + cWe have five points, so we can set up equations:For A: 3 = a*(2)^2 + b*2 + c => 4a + 2b + c = 3For B: 7 = a*(5)^2 + b*5 + c => 25a + 5b + c = 7For C: 13 = a*(11)^2 + b*11 + c => 121a + 11b + c = 13For D: 19 = a*(17)^2 + b*17 + c => 289a + 17b + c = 19For E: 29 = a*(23)^2 + b*23 + c => 529a + 23b + c = 29Hmm, solving this system might be complicated, but let me see if it's consistent.Subtract equation A from B:(25a +5b +c) - (4a +2b +c) = 7 - 3 => 21a + 3b = 4Similarly, subtract B from C:(121a +11b +c) - (25a +5b +c) = 13 -7 => 96a +6b =6 => 16a + b =1Subtract C from D:(289a +17b +c) - (121a +11b +c) =19 -13 => 168a +6b=6 =>28a + b=1Subtract D from E:(529a +23b +c) - (289a +17b +c)=29 -19 =>240a +6b=10 =>40a + b= (10/6)=5/3≈1.6667So, now we have:From B - A: 21a + 3b =4 --> let's call this equation (1)From C - B: 16a + b =1 --> equation (2)From D - C:28a + b =1 --> equation (3)From E - D:40a + b =5/3 --> equation (4)Wait, equation (2):16a + b =1Equation (3):28a + b =1Subtract equation (2) from equation (3):(28a + b) - (16a + b)=1 -1 =>12a=0 =>a=0If a=0, then from equation (2):16*0 + b=1 =>b=1Then, from equation (1):21*0 +3*1=4 =>3=4? That's not possible. Contradiction.So, the points do not lie on a quadratic curve. Therefore, they form a convex pentagon, and the area calculation should be correct.Wait, but the area seems small. Maybe I made a mistake in the shoelace formula.Let me try recalculating Sum1 and Sum2.Sum1:x1y2 =2*7=14x2y3=5*13=65x3y4=11*19=209x4y5=17*29=493x5y6=23*3=69Total Sum1=14+65=79; 79+209=288; 288+493=781; 781+69=850Sum2:y1x2=3*5=15y2x3=7*11=77y3x4=13*17=221y4x5=19*23=437y5x6=29*2=58Total Sum2=15+77=92; 92+221=313; 313+437=750; 750+58=808Difference:850-808=42Area=42/2=21Hmm, same result. Maybe it's correct. Maybe the area is indeed 21.Alternatively, perhaps the points are not in order? Maybe I should try a different order.Wait, the problem says "the pentagon formed by these five monuments." It doesn't specify the order, so maybe I assumed the wrong order.Looking at the coordinates, perhaps they are not in order? Let me check the order again.Wait, if I plot them:A(2,3), B(5,7), C(11,13), D(17,19), E(23,29)Plotting these, they seem to lie on a straight line? Wait, no, because the slope between A and B is (7-3)/(5-2)=4/3≈1.333Slope between B and C: (13-7)/(11-5)=6/6=1Slope between C and D: (19-13)/(17-11)=6/6=1Slope between D and E: (29-19)/(23-17)=10/6≈1.666So, the slopes are changing, so it's not a straight line. So, the pentagon is convex, and the shoelace formula should apply.Wait, maybe I should try a different order. Maybe the points are not given in order. Let me see.Looking at the coordinates, perhaps the order is not A-B-C-D-E, but something else.Wait, let me think about the coordinates:A: (2,3)B: (5,7)C: (11,13)D: (17,19)E: (23,29)If I plot these, they seem to be progressing in a way that each subsequent point is further to the northeast, but not in a straight line. So, connecting them in the given order should form a convex pentagon.Alternatively, maybe the order is different. Let me try another order.Wait, another thought: maybe the points are given in a different sequence, not the order around the pentagon. For example, maybe A is connected to C, then to E, etc. But without more information, it's hard to tell.Wait, the problem says "the pentagon formed by these five monuments." So, it's a convex pentagon, and the order is likely given in a sequential manner.Alternatively, perhaps the shoelace formula is giving me 21 because the points are arranged in such a way that the area is indeed small. Maybe the coordinates are scaled down? Or maybe it's correct.Wait, let me check the distances between the points to get an idea of the scale.Distance between A and B: sqrt((5-2)^2 + (7-3)^2)=sqrt(9+16)=sqrt(25)=5Distance between B and C: sqrt((11-5)^2 + (13-7)^2)=sqrt(36+36)=sqrt(72)=6√2≈8.485Distance between C and D: sqrt((17-11)^2 + (19-13)^2)=sqrt(36+36)=sqrt(72)=6√2≈8.485Distance between D and E: sqrt((23-17)^2 + (29-19)^2)=sqrt(36+100)=sqrt(136)=2√34≈11.661Distance between E and A: sqrt((23-2)^2 + (29-3)^2)=sqrt(441+676)=sqrt(1117)≈33.42Wait, that's a huge distance. So, the side from E back to A is very long, which might make the pentagon quite large. But according to the shoelace formula, the area is only 21. That seems inconsistent.Wait, maybe I made a mistake in the shoelace formula. Let me try again, but this time, I'll write out all the terms clearly.List of points in order:1. A: (2,3)2. B: (5,7)3. C: (11,13)4. D: (17,19)5. E: (23,29)6. A: (2,3)Compute Sum1:(x1*y2) = 2*7 =14(x2*y3)=5*13=65(x3*y4)=11*19=209(x4*y5)=17*29=493(x5*y6)=23*3=69Sum1=14+65+209+493+69=850Compute Sum2:(y1*x2)=3*5=15(y2*x3)=7*11=77(y3*x4)=13*17=221(y4*x5)=19*23=437(y5*x6)=29*2=58Sum2=15+77+221+437+58=808Difference:850-808=42Area=42/2=21Hmm, same result. Maybe the area is indeed 21. Alternatively, perhaps the coordinates are in a different order.Wait, another idea: maybe the points are not listed in the order they appear around the pentagon. For example, maybe they are listed in the order of their discovery or something else, not the polygon order.If that's the case, the shoelace formula won't work correctly because the order is messed up. So, perhaps I need to arrange the points in the correct order around the pentagon.How can I do that? Maybe by plotting them or finding the convex hull.Given the coordinates, let me try to figure out the correct order.Looking at the points:A(2,3), B(5,7), C(11,13), D(17,19), E(23,29)Plotting roughly:A is the southwest point.B is northeast of A.C is northeast of B.D is northeast of C.E is northeast of D.So, if I connect them in the order A-B-C-D-E-A, it's a convex pentagon.But when I calculated the area, it's 21. Maybe that's correct.Alternatively, maybe the coordinates are in a different order. Let me try a different order.Suppose the order is A, C, E, D, B, A.Let me compute the area with this order.Points:1. A: (2,3)2. C: (11,13)3. E: (23,29)4. D: (17,19)5. B: (5,7)6. A: (2,3)Compute Sum1:x1y2=2*13=26x2y3=11*29=319x3y4=23*19=437x4y5=17*7=119x5y6=5*3=15Sum1=26+319=345; 345+437=782; 782+119=901; 901+15=916Sum2:y1x2=3*11=33y2x3=13*23=299y3x4=29*17=493y4x5=19*5=95y5x6=7*2=14Sum2=33+299=332; 332+493=825; 825+95=920; 920+14=934Difference:916 -934= -18Absolute value:18Area=18/2=9That's even smaller. So, probably not the correct order.Alternatively, maybe A, B, D, C, E, A.Let me try:Points:1. A: (2,3)2. B: (5,7)3. D: (17,19)4. C: (11,13)5. E: (23,29)6. A: (2,3)Compute Sum1:x1y2=2*7=14x2y3=5*19=95x3y4=17*13=221x4y5=11*29=319x5y6=23*3=69Sum1=14+95=109; 109+221=330; 330+319=649; 649+69=718Sum2:y1x2=3*5=15y2x3=7*17=119y3x4=19*11=209y4x5=13*23=299y5x6=29*2=58Sum2=15+119=134; 134+209=343; 343+299=642; 642+58=700Difference:718 -700=18Area=18/2=9Again, smaller area. So, probably not the correct order.Alternatively, maybe A, E, D, C, B, A.Let me try:Points:1. A: (2,3)2. E: (23,29)3. D: (17,19)4. C: (11,13)5. B: (5,7)6. A: (2,3)Compute Sum1:x1y2=2*29=58x2y3=23*19=437x3y4=17*13=221x4y5=11*7=77x5y6=5*3=15Sum1=58+437=495; 495+221=716; 716+77=793; 793+15=808Sum2:y1x2=3*23=69y2x3=29*17=493y3x4=19*11=209y4x5=13*5=65y5x6=7*2=14Sum2=69+493=562; 562+209=771; 771+65=836; 836+14=850Difference:808 -850= -42Absolute value:42Area=42/2=21Same as before. So, regardless of the order, as long as it's a convex pentagon, the area is 21.Wait, but in this case, the order was A-E-D-C-B-A, which is different from the original order, but the area is the same. So, maybe the shoelace formula is order-independent as long as the polygon is convex and the points are listed in order.Wait, no, the shoelace formula requires the points to be ordered either clockwise or counterclockwise without crossing. So, if I change the order, the area can change or stay the same depending on the traversal.But in this case, both orders gave me the same area. So, maybe 21 is correct.Alternatively, maybe I should use vectors or divide the pentagon into triangles and sum their areas.Let me try that.Divide the pentagon into three triangles: A-B-C, A-C-D, A-D-E.Wait, no, that might not cover the entire area. Alternatively, divide it into triangles from a common point.Alternatively, use the shoelace formula but ensure the points are ordered correctly.Wait, another idea: perhaps the points are colinear in a certain way, making the area small.Wait, looking at the coordinates:A(2,3), B(5,7), C(11,13), D(17,19), E(23,29)Let me check if these points lie on a straight line.Compute the slope between A and B: (7-3)/(5-2)=4/3≈1.333Slope between B and C: (13-7)/(11-5)=6/6=1Slope between C and D: (19-13)/(17-11)=6/6=1Slope between D and E: (29-19)/(23-17)=10/6≈1.666So, the slopes are changing, so it's not a straight line.Alternatively, maybe they lie on a quadratic curve? Earlier, I tried that and got a contradiction, so probably not.Alternatively, maybe they lie on a cubic curve? That might be overcomplicating.Alternatively, perhaps the area is indeed 21. Maybe the units are not in kilometers or meters, but in some other scale, making the area seem small.Alternatively, maybe I made a mistake in the shoelace formula by not considering the direction.Wait, the shoelace formula gives a positive area if the points are ordered counterclockwise and negative if clockwise, but we take the absolute value. So, regardless, the area is 21.Alternatively, perhaps the area is 21 square units, and that's the answer.Okay, maybe I should accept that and move on to part 2.Part 2 is about determining the constants a, b, c, d for the linear transformation:X = a x + b yY = c x + d yGiven that monument A(2,3) transforms to (19,25), and monument B(5,7) transforms to (47,61).So, we have two points and their transformations, which gives us four equations.For point A:X = a*2 + b*3 =19Y = c*2 + d*3 =25For point B:X = a*5 + b*7 =47Y = c*5 + d*7 =61So, we have four equations:1. 2a + 3b =192. 5a +7b=473. 2c +3d=254.5c +7d=61We can solve for a and b first, then solve for c and d.Let's solve equations 1 and 2 for a and b.Equation1: 2a +3b=19Equation2:5a +7b=47Let me use elimination.Multiply equation1 by 5: 10a +15b=95Multiply equation2 by 2:10a +14b=94Subtract equation2*2 from equation1*5:(10a +15b) - (10a +14b)=95 -94Which gives: b=1Now, plug b=1 into equation1:2a +3*1=19 =>2a=16 =>a=8So, a=8, b=1Now, solve equations3 and4 for c and d.Equation3:2c +3d=25Equation4:5c +7d=61Again, use elimination.Multiply equation3 by5:10c +15d=125Multiply equation4 by2:10c +14d=122Subtract equation4*2 from equation3*5:(10c +15d) - (10c +14d)=125 -122Which gives: d=3Now, plug d=3 into equation3:2c +3*3=25 =>2c=25-9=16 =>c=8So, c=8, d=3Therefore, the constants are:a=8, b=1, c=8, d=3Let me verify these results.For point A(2,3):X=8*2 +1*3=16+3=19 ✓Y=8*2 +3*3=16+9=25 ✓For point B(5,7):X=8*5 +1*7=40+7=47 ✓Y=8*5 +3*7=40+21=61 ✓Perfect, so the constants are correct.So, summarizing:1. The area of the pentagon is 21 square units.2. The transformation constants are a=8, b=1, c=8, d=3.Now, combining these results to provide insights into the historical context.The area calculation shows that the monuments form a pentagon with a specific area, which might have been used as a key or reference in the espionage network. The linear transformation reveals a method used to encode or decode messages by transforming the coordinates, possibly to obscure the true locations or to map them onto another system.This could imply that the network used both geometric properties (like the area) and linear algebra techniques (like coordinate transformations) to securely transmit messages during WWII. The specific constants in the transformation might have been known only to certain members, adding another layer of security.Overall, these mathematical methods demonstrate the sophistication of the espionage techniques used, leveraging both geometry and linear transformations to ensure the confidentiality of their communications.</think>
❓:An insurance industry professional is analyzing the impact of well-trained firefighters on reducing property damage and subsequent insurance claims in a densely populated urban area. The professional has gathered data over the past 10 years and created a predictive model based on the following factors:1. The average response time (R, in minutes) of the firefighters to reach a fire incident.2. The average property damage (D, in thousands of dollars) per fire incident.3. The number of fire incidents (N) per year.4. The reduction factor (F) that represents the effectiveness of well-trained firefighters, where ( 0 leq F leq 1 ).The professional has observed that the average property damage per fire incident can be modeled by the equation:[ D = 50e^{-F frac{R}{10}} ]Sub-problem 1:Given that the average response time ( R ) is 8 minutes and the reduction factor ( F ) is 0.5, calculate the average property damage ( D ) per fire incident.Sub-problem 2:If the number of fire incidents ( N ) per year is modeled by a Poisson distribution with a mean rate parameter (lambda = 20), find the probability that there will be exactly 25 fire incidents in a given year.
🧠:<think>Alright, so I have two sub-problems to solve here. Let me take them one at a time. Starting with Sub-problem 1. It says that the average response time R is 8 minutes and the reduction factor F is 0.5. I need to calculate the average property damage D per fire incident using the given equation: D = 50e^{-F*(R/10)}. Okay, so let me plug in the values. R is 8, F is 0.5. So substituting these into the equation, it becomes D = 50e^{-0.5*(8/10)}. Let me compute the exponent first. 8 divided by 10 is 0.8. Then, multiplying by 0.5 gives 0.4. So the exponent is -0.4. So now, D = 50e^{-0.4}. I need to calculate e^{-0.4}. I remember that e is approximately 2.71828. So e^{-0.4} is 1 divided by e^{0.4}. Let me compute e^{0.4}. I know that e^{0.4} is approximately... Hmm, I might need to use a calculator for this, but since I don't have one, maybe I can recall that e^{0.4} is roughly 1.4918. So 1 divided by 1.4918 is approximately 0.6703. Therefore, D = 50 * 0.6703. Let me compute that. 50 times 0.67 is 33.5, and 50 times 0.0003 is 0.015, so adding them together gives approximately 33.515. Wait, but maybe I should be more precise with e^{-0.4}. Let me think. The exact value of e^{-0.4} can be calculated using the Taylor series expansion or perhaps a better approximation. Alternatively, I can remember that ln(2) is approximately 0.6931, so e^{-0.4} is e^{-0.6931 + 0.2931} which is e^{-ln(2)} * e^{0.2931} = (1/2) * e^{0.2931}. Now, e^{0.2931} is approximately... Let me recall that e^{0.3} is about 1.3499. Since 0.2931 is slightly less than 0.3, maybe around 1.34. So, 1/2 * 1.34 is approximately 0.67. So that still gives me D ≈ 50 * 0.67 = 33.5. But perhaps I should use a calculator for better precision. Alternatively, I can use the fact that e^{-0.4} is approximately 0.67032. So, 50 * 0.67032 is exactly 33.516. So, D is approximately 33.516 thousand dollars. Wait, but the question says to calculate D, so maybe I should present it as 33.52 thousand dollars, rounding to two decimal places. Alternatively, if it's acceptable, I can write it as 33.5 thousand dollars. Hmm, but since the original equation uses 50, which is an exact number, and the exponent is precise, maybe I should keep more decimal places. Alternatively, perhaps I should just compute it step by step. Let me try to compute e^{-0.4} more accurately. I know that e^{-0.4} can be calculated using the Taylor series expansion around 0: e^x = 1 + x + x^2/2! + x^3/3! + x^4/4! + ... So, for x = -0.4, e^{-0.4} = 1 - 0.4 + (0.4)^2/2 - (0.4)^3/6 + (0.4)^4/24 - (0.4)^5/120 + ... Let me compute each term:1st term: 12nd term: -0.43rd term: (0.16)/2 = 0.084th term: (-0.064)/6 ≈ -0.01066675th term: (0.0256)/24 ≈ 0.00106676th term: (-0.01024)/120 ≈ -0.00008537th term: (0.004096)/720 ≈ 0.00000568Adding these up:1 - 0.4 = 0.60.6 + 0.08 = 0.680.68 - 0.0106667 ≈ 0.66933330.6693333 + 0.0010667 ≈ 0.67040.6704 - 0.0000853 ≈ 0.67031470.6703147 + 0.00000568 ≈ 0.67032038So, e^{-0.4} ≈ 0.67032. Therefore, D = 50 * 0.67032 = 33.516. So, the average property damage D is approximately 33.516 thousand dollars. If we round to two decimal places, it's 33.52 thousand dollars. Alternatively, maybe the question expects an exact expression, but since it's a numerical value, I think 33.52 is acceptable. Moving on to Sub-problem 2. It says that the number of fire incidents N per year follows a Poisson distribution with a mean rate parameter λ = 20. We need to find the probability that there will be exactly 25 fire incidents in a given year. The Poisson probability mass function is given by P(N = k) = (λ^k * e^{-λ}) / k! So, substituting λ = 20 and k = 25, we have P(N = 25) = (20^{25} * e^{-20}) / 25! Calculating this directly might be challenging due to the large exponents and factorials, but perhaps we can compute it step by step or use logarithms to simplify. Alternatively, since 20 is a relatively large λ, and 25 is close to 20, maybe we can use the normal approximation to the Poisson distribution, but the question doesn't specify, so I think we should compute it exactly. But let's see. The formula is P(N=25) = (20^25 * e^{-20}) / 25! First, let's compute 20^25. That's a huge number. Similarly, 25! is also a huge number. So, perhaps we can compute the logarithm of the probability and then exponentiate it. Alternatively, we can compute the terms step by step, simplifying as we go. Let me try to compute the numerator and denominator separately. Numerator: 20^25 * e^{-20}Denominator: 25!But 20^25 is 20 multiplied by itself 25 times, which is 20^25. Similarly, 25! is 25 factorial. Alternatively, we can write the Poisson probability as:P(N=25) = (20^25 / 25!) * e^{-20}So, let's compute 20^25 / 25! first, then multiply by e^{-20}.But computing 20^25 / 25! is still a bit tricky. Let me see if I can compute it step by step.Alternatively, perhaps I can use the property of Poisson probabilities, which is that P(N=k) = P(N=k-1) * λ / k. So, starting from P(N=0), we can compute P(N=1), P(N=2), ..., up to P(N=25). But that might take a long time, but perhaps manageable.Alternatively, I can use logarithms to compute the terms.Let me try to compute ln(P(N=25)) = ln(20^25) + ln(e^{-20}) - ln(25!) Which is 25 ln(20) - 20 - ln(25!) Compute each term:25 ln(20): ln(20) is approximately 2.9957, so 25 * 2.9957 ≈ 74.8925-20: straightforward, subtract 20.ln(25!): We can use Stirling's approximation for ln(n!) which is n ln(n) - n + (ln(2πn))/2. So, ln(25!) ≈ 25 ln(25) - 25 + (ln(2π*25))/2Compute each part:25 ln(25): ln(25) is approximately 3.2189, so 25 * 3.2189 ≈ 80.4725-25: subtract 25, so 80.4725 - 25 = 55.4725(ln(2π*25))/2: 2π*25 ≈ 157.0796, ln(157.0796) ≈ 5.0566, divided by 2 is ≈ 2.5283So, ln(25!) ≈ 55.4725 + 2.5283 ≈ 58.0008Therefore, ln(P(N=25)) ≈ 74.8925 - 20 - 58.0008 ≈ 74.8925 - 78.0008 ≈ -3.1083So, P(N=25) ≈ e^{-3.1083} ≈ ?Compute e^{-3.1083}: e^{-3} is approximately 0.0498, and e^{-0.1083} is approximately 0.898. So, multiplying these together: 0.0498 * 0.898 ≈ 0.0447.Alternatively, using a calculator, e^{-3.1083} ≈ 0.0447.But let me check the exact value using a calculator. Alternatively, perhaps I made a mistake in the Stirling approximation. Let me verify the exact value of ln(25!).Wait, 25! is 15511210043330985984000000. Taking the natural log of that: ln(15511210043330985984000000). But that's a huge number. Alternatively, perhaps I can compute ln(25!) using the exact value. Alternatively, perhaps I can use the exact value of ln(25!) which is approximately 58.0008 as computed before. So, proceeding with that, the approximation gives P(N=25) ≈ 0.0447 or 4.47%.But let me see if I can compute it more accurately. Alternatively, perhaps I can use the exact formula.Alternatively, perhaps I can use the fact that for Poisson distribution, the probability mass function can be computed using the formula, and perhaps I can use a calculator or software, but since I'm doing it manually, let me try to compute it step by step.Alternatively, perhaps I can use the recursive formula: P(k) = P(k-1) * λ / kSo, starting from P(0) = e^{-20} ≈ 2.0611536 * 10^{-9}Then, P(1) = P(0) * 20 / 1 ≈ 2.0611536 * 10^{-9} * 20 ≈ 4.1223072 * 10^{-8}P(2) = P(1) * 20 / 2 ≈ 4.1223072 * 10^{-8} * 10 ≈ 4.1223072 * 10^{-7}P(3) = P(2) * 20 / 3 ≈ 4.1223072 * 10^{-7} * 6.6666667 ≈ 2.7482048 * 10^{-6}P(4) = P(3) * 20 / 4 ≈ 2.7482048 * 10^{-6} * 5 ≈ 1.3741024 * 10^{-5}P(5) = P(4) * 20 / 5 ≈ 1.3741024 * 10^{-5} * 4 ≈ 5.4964096 * 10^{-5}P(6) = P(5) * 20 / 6 ≈ 5.4964096 * 10^{-5} * 3.3333333 ≈ 1.8321365 * 10^{-4}P(7) = P(6) * 20 / 7 ≈ 1.8321365 * 10^{-4} * 2.8571429 ≈ 5.2289614 * 10^{-4}P(8) = P(7) * 20 / 8 ≈ 5.2289614 * 10^{-4} * 2.5 ≈ 1.30724035 * 10^{-3}P(9) = P(8) * 20 / 9 ≈ 1.30724035 * 10^{-3} * 2.2222222 ≈ 2.9027563 * 10^{-3}P(10) = P(9) * 20 / 10 ≈ 2.9027563 * 10^{-3} * 2 ≈ 5.8055126 * 10^{-3}P(11) = P(10) * 20 / 11 ≈ 5.8055126 * 10^{-3} * 1.8181818 ≈ 1.0555463 * 10^{-2}P(12) = P(11) * 20 / 12 ≈ 1.0555463 * 10^{-2} * 1.6666667 ≈ 1.7592438 * 10^{-2}P(13) = P(12) * 20 / 13 ≈ 1.7592438 * 10^{-2} * 1.5384615 ≈ 2.707206 * 10^{-2}P(14) = P(13) * 20 / 14 ≈ 2.707206 * 10^{-2} * 1.4285714 ≈ 3.8602943 * 10^{-2}P(15) = P(14) * 20 / 15 ≈ 3.8602943 * 10^{-2} * 1.3333333 ≈ 5.147059 * 10^{-2}P(16) = P(15) * 20 / 16 ≈ 5.147059 * 10^{-2} * 1.25 ≈ 6.4338238 * 10^{-2}P(17) = P(16) * 20 / 17 ≈ 6.4338238 * 10^{-2} * 1.1764706 ≈ 7.568543 * 10^{-2}P(18) = P(17) * 20 / 18 ≈ 7.568543 * 10^{-2} * 1.1111111 ≈ 8.409492 * 10^{-2}P(19) = P(18) * 20 / 19 ≈ 8.409492 * 10^{-2} * 1.0526316 ≈ 8.857705 * 10^{-2}P(20) = P(19) * 20 / 20 ≈ 8.857705 * 10^{-2} * 1 ≈ 8.857705 * 10^{-2}P(21) = P(20) * 20 / 21 ≈ 8.857705 * 10^{-2} * 0.95238095 ≈ 8.452381 * 10^{-2}P(22) = P(21) * 20 / 22 ≈ 8.452381 * 10^{-2} * 0.9090909 ≈ 7.68421 * 10^{-2}P(23) = P(22) * 20 / 23 ≈ 7.68421 * 10^{-2} * 0.8695652 ≈ 6.68421 * 10^{-2}P(24) = P(23) * 20 / 24 ≈ 6.68421 * 10^{-2} * 0.8333333 ≈ 5.570175 * 10^{-2}P(25) = P(24) * 20 / 25 ≈ 5.570175 * 10^{-2} * 0.8 ≈ 4.45614 * 10^{-2}So, according to this recursive calculation, P(N=25) ≈ 0.04456 or 4.456%.Comparing this with the earlier approximation using Stirling's formula, which gave approximately 4.47%, they are very close. So, the probability is approximately 4.46%.Alternatively, perhaps I can use a calculator to compute it more accurately. Let me check.Using a calculator, the exact value of P(N=25) when λ=20 is approximately 0.04456, which is about 4.46%.So, rounding to four decimal places, it's 0.0446 or 4.46%.Alternatively, if we want to present it as a probability, it's approximately 4.46%.Therefore, the probability of exactly 25 fire incidents in a given year is approximately 4.46%.But let me double-check the recursive calculation. When I computed P(25), I got approximately 0.04456, which is 4.456%. So, rounding to three decimal places, it's 0.045 or 4.5%, but perhaps the exact value is closer to 4.46%.Alternatively, perhaps I can use the exact formula with more precise calculations.Alternatively, perhaps I can use the fact that the Poisson probability can be calculated using the formula:P(N=k) = (λ^k e^{-λ}) / k!So, let's compute it step by step with more precision.First, compute λ^k: 20^25.20^1 = 2020^2 = 40020^3 = 800020^4 = 160,00020^5 = 3,200,00020^6 = 64,000,00020^7 = 1,280,000,00020^8 = 25,600,000,00020^9 = 512,000,000,00020^10 = 10,240,000,000,00020^11 = 204,800,000,000,00020^12 = 4,096,000,000,000,00020^13 = 81,920,000,000,000,00020^14 = 1,638,400,000,000,000,00020^15 = 32,768,000,000,000,000,00020^16 = 655,360,000,000,000,000,00020^17 = 13,107,200,000,000,000,000,00020^18 = 262,144,000,000,000,000,000,00020^19 = 5,242,880,000,000,000,000,000,00020^20 = 104,857,600,000,000,000,000,000,00020^21 = 2,097,152,000,000,000,000,000,000,00020^22 = 41,943,040,000,000,000,000,000,000,00020^23 = 838,860,800,000,000,000,000,000,000,00020^24 = 16,777,216,000,000,000,000,000,000,000,00020^25 = 335,544,320,000,000,000,000,000,000,000,000So, 20^25 is 3.3554432 x 10^33.Now, compute e^{-20}. e^{-20} is approximately 2.061153622438558 x 10^{-9}.Now, compute 25!:25! = 15511210043330985984000000Which is approximately 1.551121 x 10^{25}.So, putting it all together:P(N=25) = (3.3554432 x 10^{33} * 2.061153622438558 x 10^{-9}) / 1.551121 x 10^{25}First, multiply the numerator:3.3554432 x 10^{33} * 2.061153622438558 x 10^{-9} = (3.3554432 * 2.061153622438558) x 10^{24}Compute 3.3554432 * 2.061153622438558:Let me compute this:3.3554432 * 2 = 6.71088643.3554432 * 0.061153622438558 ≈ 3.3554432 * 0.06 ≈ 0.201326592, and 3.3554432 * 0.001153622438558 ≈ ~0.003873So total ≈ 6.7108864 + 0.201326592 + 0.003873 ≈ 6.916086So, approximately 6.916086 x 10^{24}Now, divide by 1.551121 x 10^{25}:(6.916086 x 10^{24}) / (1.551121 x 10^{25}) = (6.916086 / 15.51121) x 10^{-1}Compute 6.916086 / 15.51121:15.51121 goes into 6.916086 approximately 0.446 times.So, 0.446 x 10^{-1} = 0.0446Therefore, P(N=25) ≈ 0.0446 or 4.46%.So, that matches the earlier recursive calculation. Therefore, the probability is approximately 4.46%.Therefore, the answers are:Sub-problem 1: D ≈ 33.52 thousand dollars.Sub-problem 2: Probability ≈ 4.46%.But let me check if I can express these more precisely.For Sub-problem 1, since e^{-0.4} is approximately 0.67032, so 50 * 0.67032 = 33.516, which is 33.516 thousand dollars. So, if we round to two decimal places, it's 33.52.For Sub-problem 2, the exact value is approximately 0.04456, which is 4.456%, so rounding to three decimal places, 0.0446 or 4.46%.Therefore, the final answers are:Sub-problem 1: D = 33.52 thousand dollars.Sub-problem 2: Probability ≈ 4.46%.</think>
❓:An employment counselor is working with three local businesses (A, B, and C) to develop inclusive hiring practices. Each business has agreed to allocate a certain percentage of their total job openings to candidates from underrepresented groups. The counselor wants to model the potential impact on the diversity of the workforce.1. Business A plans to fill 40% of its 150 open positions with candidates from underrepresented groups. Business B plans to do the same with 35% of its 200 open positions, and Business C with 50% of its 120 open positions. The counselor proposes a model where these percentages are increased by a multiplier "m" for all businesses to increase the overall diversity impact. If each business increases its percentage by the same multiplier "m," calculate the value of "m" that would result in a total of 200 positions filled by candidates from underrepresented groups across all three businesses.2. After implementing the multiplier "m," the counselor wants to evaluate the change in the diversity ratio, defined as the ratio of positions filled by candidates from underrepresented groups to the total number of positions across all three businesses. If the initial diversity ratio was 0.35, calculate the new diversity ratio and determine the percentage change in the diversity ratio due to the multiplier "m."
🧠:<think>Okay, so I have this problem about an employment counselor working with three businesses to increase hiring from underrepresented groups. There are two parts to the problem, and I need to figure out both. Let me start by understanding what each part is asking.First, part 1: Each business has a certain number of open positions and a percentage they plan to fill with underrepresented candidates. The counselor wants to increase these percentages by a multiplier "m" for all businesses so that the total number of positions filled by underrepresented groups becomes 200. I need to find the value of "m" that achieves this.Let me break down the given information:- Business A: 150 positions, 40% allocated.- Business B: 200 positions, 35% allocated.- Business C: 120 positions, 50% allocated.So, initially, without any multiplier, the number of positions filled by underrepresented groups would be:- A: 40% of 150 = 0.4 * 150 = 60- B: 35% of 200 = 0.35 * 200 = 70- C: 50% of 120 = 0.5 * 120 = 60Adding these up: 60 + 70 + 60 = 190 positions.But the counselor wants the total to be 200. So, we need to increase each business's percentage by a multiplier "m" such that the total becomes 200.Wait, does that mean we're increasing each percentage by m times? Or is it adding m to each percentage? Hmm, the problem says "increased by a multiplier 'm'". So, I think it means multiplying each percentage by m. So, the new percentage for each business would be original percentage * m.But let me confirm: If m is a multiplier, then yes, multiplying the original percentage by m would increase it. So, for example, if m is 1.1, each percentage would increase by 10%.So, the new number of positions filled by underrepresented groups for each business would be:- A: (0.4 * m) * 150- B: (0.35 * m) * 200- C: (0.5 * m) * 120And the sum of these should be 200.So, I can write the equation:(0.4m * 150) + (0.35m * 200) + (0.5m * 120) = 200Let me compute each term:First term: 0.4m * 150 = 60mSecond term: 0.35m * 200 = 70mThird term: 0.5m * 120 = 60mAdding them up: 60m + 70m + 60m = 190mSo, 190m = 200Therefore, m = 200 / 190 ≈ 1.0526So, m is approximately 1.0526, which is about a 5.26% increase.Wait, let me double-check my calculations.Original positions:A: 0.4*150=60B: 0.35*200=70C: 0.5*120=60Total: 60+70+60=190After multiplier m:A: 0.4m*150=60mB: 0.35m*200=70mC: 0.5m*120=60mTotal: 60m +70m +60m=190mSet equal to 200: 190m=200 => m=200/190≈1.0526Yes, that seems correct.So, m≈1.0526 or exactly 20/19≈1.0526.Okay, so that's part 1.Now, part 2: After implementing the multiplier m, the counselor wants to evaluate the change in the diversity ratio. The diversity ratio is defined as the ratio of positions filled by underrepresented groups to the total number of positions across all three businesses.Initially, the diversity ratio was 0.35. So, I need to find the new diversity ratio after applying m, and then determine the percentage change.First, let's compute the total number of positions across all three businesses.Business A: 150Business B: 200Business C: 120Total positions: 150 + 200 + 120 = 470Initially, positions filled by underrepresented groups: 190So, initial diversity ratio: 190 / 470 ≈ 0.4043Wait, but the problem says the initial diversity ratio was 0.35. Hmm, that's conflicting with my calculation.Wait, maybe I misunderstood. Let me check.Wait, the problem says: "the initial diversity ratio was 0.35". But according to my calculation, it's 190/470≈0.4043.Hmm, that's a discrepancy. Maybe the initial diversity ratio is not based on the given allocations? Or perhaps I misread the problem.Wait, let me read again:"Business A plans to fill 40% of its 150 open positions with candidates from underrepresented groups. Business B plans to do the same with 35% of its 200 open positions, and Business C with 50% of its 120 open positions."So, the initial plan is 40%, 35%, 50%, leading to 60,70,60, totaling 190.Total positions: 150+200+120=470.So, 190/470≈0.4043.But the problem says the initial diversity ratio was 0.35. Hmm, that suggests that perhaps the initial diversity ratio is not based on their current plans, but perhaps their current actual hires?Wait, the problem says: "the counselor wants to model the potential impact on the diversity of the workforce." So, perhaps the initial diversity ratio is 0.35, which is the current ratio, not based on their current plans.Wait, the problem is a bit ambiguous. Let me read again:"Each business has agreed to allocate a certain percentage of their total job openings to candidates from underrepresented groups. The counselor proposes a model where these percentages are increased by a multiplier 'm' for all businesses to increase the overall diversity impact."So, the initial plan is 40%,35%,50%, which would lead to 190/470≈0.4043.But the problem says "the initial diversity ratio was 0.35". So, perhaps the initial diversity ratio is 0.35, which is different from their current plans? Or maybe the initial diversity ratio is based on their current hires, not their plans.Wait, the problem says: "the counselor wants to model the potential impact on the diversity of the workforce." So, the businesses have agreed to allocate certain percentages, which would result in a certain diversity ratio, but the counselor is considering increasing those percentages.But the problem says the initial diversity ratio was 0.35. So, perhaps the initial diversity ratio is 0.35, which is the current ratio, and the businesses are planning to increase it by their allocated percentages, but the counselor is further increasing it by m.Wait, this is confusing.Wait, let me read the problem again:"An employment counselor is working with three local businesses (A, B, and C) to develop inclusive hiring practices. Each business has agreed to allocate a certain percentage of their total job openings to candidates from underrepresented groups. The counselor wants to model the potential impact on the diversity of the workforce.1. Business A plans to fill 40% of its 150 open positions with candidates from underrepresented groups. Business B plans to do the same with 35% of its 200 open positions, and Business C with 50% of its 120 open positions. The counselor proposes a model where these percentages are increased by a multiplier 'm' for all businesses to increase the overall diversity impact. If each business increases its percentage by the same multiplier 'm,' calculate the value of 'm' that would result in a total of 200 positions filled by candidates from underrepresented groups across all three businesses.2. After implementing the multiplier 'm,' the counselor wants to evaluate the change in the diversity ratio, defined as the ratio of positions filled by candidates from underrepresented groups to the total number of positions across all three businesses. If the initial diversity ratio was 0.35, calculate the new diversity ratio and determine the percentage change in the diversity ratio due to the multiplier 'm.'"So, in part 1, the businesses have agreed to allocate certain percentages (40%,35%,50%), which would result in 190 positions. The counselor wants to increase these percentages by a multiplier m so that the total becomes 200.In part 2, the initial diversity ratio is given as 0.35, which is separate from the businesses' current plans. So, perhaps the initial diversity ratio is the current state before any of the businesses' plans or the counselor's multiplier. So, the initial diversity ratio is 0.35, and then after the businesses implement their plans with the multiplier m, the diversity ratio changes.Wait, but the problem says: "the initial diversity ratio was 0.35". So, perhaps the initial diversity ratio is 0.35, and then the businesses have agreed to allocate certain percentages, which would result in a higher diversity ratio, and then the counselor is further increasing it by m to reach 200 positions.But the problem is a bit unclear. Let me try to parse it.The businesses have agreed to allocate certain percentages (40%,35%,50%). The counselor wants to model the impact of increasing these percentages by a multiplier m. The first part is to find m such that the total positions become 200.Then, part 2 is about the diversity ratio. The initial diversity ratio was 0.35, so perhaps that's before any of the businesses' plans. So, after the businesses implement their plans with the multiplier m, the diversity ratio becomes higher.Wait, but in part 1, the businesses' plans without any multiplier would result in 190 positions, which is 190/470≈0.4043. So, if the initial diversity ratio was 0.35, perhaps that's the current ratio, and the businesses' plans would increase it to 0.4043, and then the counselor's multiplier m would increase it further to 200 positions, which is 200/470≈0.4255.But the problem says in part 2: "the initial diversity ratio was 0.35", so perhaps the initial diversity ratio is 0.35, and then after applying the multiplier m, the diversity ratio becomes 200/470≈0.4255, so the percentage change is ((0.4255 - 0.35)/0.35)*100%.But wait, in part 1, the total positions filled by underrepresented groups becomes 200, which is 200/470≈0.4255.But the problem says in part 2: "the initial diversity ratio was 0.35", so perhaps the initial diversity ratio is 0.35, and after applying the multiplier m, the diversity ratio becomes 200/470≈0.4255, so the percentage change is ((0.4255 - 0.35)/0.35)*100%≈(0.0755/0.35)*100≈21.57%.But wait, let me think again.Alternatively, maybe the initial diversity ratio is based on the businesses' original allocations, which is 190/470≈0.4043, but the problem says the initial diversity ratio was 0.35. So, perhaps the initial diversity ratio is 0.35, and the businesses' original allocations (40%,35%,50%) would have increased it to 0.4043, and then the counselor's multiplier m increases it further to 0.4255.But the problem doesn't specify whether the initial diversity ratio is before or after the businesses' original allocations. It just says "the initial diversity ratio was 0.35".Wait, perhaps the initial diversity ratio is 0.35, and the businesses have agreed to allocate certain percentages, which would have increased it to 0.4043, but the counselor wants to increase it further by m to reach 200 positions, which is 0.4255.But the problem says in part 1: "the counselor proposes a model where these percentages are increased by a multiplier 'm' for all businesses to increase the overall diversity impact."So, the businesses have agreed to allocate certain percentages, and the counselor is increasing those percentages by m to get to 200 positions.So, the initial diversity ratio is 0.35, which is before any of the businesses' allocations or the counselor's multiplier.Wait, that might not make sense because the businesses have already agreed to allocate certain percentages, which would have already increased the diversity ratio.Wait, perhaps the initial diversity ratio is 0.35, and the businesses have agreed to allocate certain percentages, which would have increased it to 0.4043, and then the counselor's multiplier m would increase it further to 0.4255.But the problem says in part 1: "Business A plans to fill 40%... Business B... Business C... The counselor proposes a model where these percentages are increased by a multiplier 'm'... calculate the value of 'm' that would result in a total of 200 positions..."So, the businesses have agreed to allocate 40%,35%,50%, which would result in 190 positions. The counselor wants to increase those percentages by m to reach 200 positions. So, the initial diversity ratio is 0.35, which is before the businesses' allocations. So, after the businesses implement their allocations, the diversity ratio would be 190/470≈0.4043, and then after the counselor's multiplier, it becomes 200/470≈0.4255.But the problem says in part 2: "the initial diversity ratio was 0.35", so perhaps the initial diversity ratio is 0.35, and after the counselor's multiplier, it becomes 0.4255, so the percentage change is (0.4255 - 0.35)/0.35 *100≈21.57%.Alternatively, maybe the initial diversity ratio is 0.35, and the businesses' allocations would have increased it to 0.4043, and then the counselor's multiplier increases it to 0.4255, so the change is from 0.35 to 0.4255, which is a 21.57% increase.But the problem is a bit ambiguous. Let me try to clarify.The problem says:1. Businesses have agreed to allocate certain percentages (40%,35%,50%). The counselor wants to increase these percentages by m to reach 200 positions.2. The initial diversity ratio was 0.35. After implementing m, calculate the new diversity ratio and the percentage change.So, perhaps the initial diversity ratio is 0.35, which is before any of the businesses' allocations. Then, the businesses' allocations would have increased it to 190/470≈0.4043, and then the counselor's multiplier m increases it further to 200/470≈0.4255.But the problem doesn't mention the businesses' allocations in part 2, only the initial diversity ratio. So, perhaps the initial diversity ratio is 0.35, and after applying the multiplier m, the diversity ratio becomes 200/470≈0.4255.Therefore, the percentage change is ((0.4255 - 0.35)/0.35)*100≈(0.0755/0.35)*100≈21.57%.But let me think again.Alternatively, maybe the initial diversity ratio is 0.35, which is based on the businesses' original allocations. But that doesn't make sense because the businesses' original allocations would have resulted in a higher ratio.Wait, perhaps the initial diversity ratio is 0.35, and the businesses have agreed to allocate certain percentages, which would have increased it to 0.4043, but the counselor wants to increase it further to 0.4255 by using the multiplier m.But the problem says in part 1: "the counselor proposes a model where these percentages are increased by a multiplier 'm' for all businesses to increase the overall diversity impact."So, the businesses have agreed to allocate 40%,35%,50%, which would result in 190 positions, and the counselor wants to increase those percentages by m to reach 200 positions.Therefore, the initial diversity ratio is 0.35, which is before the businesses' allocations. After the businesses' allocations, it would have been 190/470≈0.4043, and after the counselor's multiplier, it becomes 200/470≈0.4255.But the problem in part 2 says: "the initial diversity ratio was 0.35", so perhaps the initial diversity ratio is 0.35, and after the counselor's multiplier, it becomes 0.4255, so the percentage change is ((0.4255 - 0.35)/0.35)*100≈21.57%.Alternatively, maybe the initial diversity ratio is 0.35, and the businesses' allocations would have increased it to 0.4043, and then the counselor's multiplier increases it to 0.4255, so the change from 0.35 to 0.4255 is a 21.57% increase.But I think the problem is that the initial diversity ratio is 0.35, and after applying the multiplier m, the diversity ratio becomes 200/470≈0.4255, so the percentage change is ((0.4255 - 0.35)/0.35)*100≈21.57%.Alternatively, if the initial diversity ratio is 0.35, and the businesses' allocations without the multiplier would have increased it to 0.4043, and then the multiplier increases it to 0.4255, then the change from 0.35 to 0.4255 is 21.57%, but the change from 0.4043 to 0.4255 is about 5.25%.But the problem says in part 2: "the initial diversity ratio was 0.35", so I think it's referring to the state before any of the businesses' allocations or the counselor's multiplier. So, the initial diversity ratio is 0.35, and after applying the multiplier m, the diversity ratio becomes 0.4255, so the percentage change is 21.57%.But let me check the total positions.Total positions: 150+200+120=470.After applying multiplier m, the number of underrepresented positions is 200, so the diversity ratio is 200/470≈0.4255.Initial diversity ratio: 0.35.So, the change is 0.4255 - 0.35 = 0.0755.Percentage change: (0.0755 / 0.35) * 100 ≈ 21.57%.So, approximately 21.57% increase.Alternatively, if the initial diversity ratio was 0.35, and the businesses' allocations without the multiplier would have increased it to 0.4043, and then the multiplier increases it to 0.4255, then the change from 0.35 to 0.4255 is 21.57%, but the change from 0.4043 to 0.4255 is about 5.25%.But the problem doesn't specify whether the initial diversity ratio is before or after the businesses' allocations. It just says "the initial diversity ratio was 0.35".Given that, I think the initial diversity ratio is 0.35, and after applying the multiplier m, the diversity ratio becomes 0.4255, so the percentage change is approximately 21.57%.But let me think again.Wait, the problem says in part 1: "Business A plans to fill 40%... Business B... Business C... The counselor proposes a model where these percentages are increased by a multiplier 'm'... calculate the value of 'm' that would result in a total of 200 positions..."So, the businesses have agreed to allocate 40%,35%,50%, which would result in 190 positions. The counselor wants to increase those percentages by m to reach 200 positions.So, the initial diversity ratio is 0.35, which is before the businesses' allocations. After the businesses' allocations, it would have been 190/470≈0.4043, and then after the counselor's multiplier, it becomes 200/470≈0.4255.But the problem in part 2 says: "the initial diversity ratio was 0.35", so perhaps the initial diversity ratio is 0.35, and after the counselor's multiplier, it becomes 0.4255, so the percentage change is 21.57%.Alternatively, if the initial diversity ratio is 0.35, and the businesses' allocations would have increased it to 0.4043, and then the counselor's multiplier increases it to 0.4255, then the change from 0.35 to 0.4255 is 21.57%, but the change from 0.4043 to 0.4255 is about 5.25%.But the problem doesn't specify whether the initial diversity ratio is before or after the businesses' allocations. It just says "the initial diversity ratio was 0.35".Given that, I think the initial diversity ratio is 0.35, and after applying the multiplier m, the diversity ratio becomes 0.4255, so the percentage change is approximately 21.57%.But to be precise, let me calculate it exactly.Total positions: 470.After multiplier m, underrepresented positions: 200.Diversity ratio: 200/470.Let me compute 200/470:200 ÷ 470 ≈ 0.4255319149.Initial diversity ratio: 0.35.Change: 0.4255319149 - 0.35 = 0.0755319149.Percentage change: (0.0755319149 / 0.35) * 100 ≈ (0.0755319149 / 0.35) * 100 ≈ 0.2157 * 100 ≈ 21.57%.So, approximately 21.57% increase.Alternatively, if the initial diversity ratio was 0.35, and the businesses' allocations without the multiplier would have increased it to 0.4043, then the change from 0.35 to 0.4043 is about 15.51%, and then the multiplier increases it further to 0.4255, which is an additional 5.25% increase.But the problem doesn't specify whether the initial diversity ratio is before or after the businesses' allocations. It just says "the initial diversity ratio was 0.35".Given that, I think the initial diversity ratio is 0.35, and after applying the multiplier m, the diversity ratio becomes 0.4255, so the percentage change is approximately 21.57%.But to be thorough, let me consider both scenarios.Scenario 1: Initial diversity ratio is 0.35 (before any allocations). After businesses' allocations without multiplier: 190/470≈0.4043. After multiplier: 200/470≈0.4255. So, change from 0.35 to 0.4255: 21.57%.Scenario 2: Initial diversity ratio is 0.35 (before businesses' allocations). Businesses' allocations without multiplier: 190/470≈0.4043. Then, applying multiplier m: 200/470≈0.4255. So, the change from 0.35 to 0.4255 is 21.57%.Alternatively, if the initial diversity ratio is 0.35, and the businesses' allocations without multiplier would have increased it to 0.4043, and then the multiplier increases it to 0.4255, the percentage change from 0.35 to 0.4255 is still 21.57%.Alternatively, if the initial diversity ratio is 0.35, and the businesses' allocations without multiplier would have increased it to 0.4043, and then the multiplier increases it to 0.4255, the percentage change from 0.4043 to 0.4255 is about 5.25%.But the problem says in part 2: "the initial diversity ratio was 0.35", so I think it's referring to the state before any of the businesses' allocations or the counselor's multiplier. Therefore, the initial diversity ratio is 0.35, and after applying the multiplier m, it becomes 0.4255, so the percentage change is 21.57%.Therefore, the new diversity ratio is approximately 0.4255, and the percentage change is approximately 21.57%.But let me compute it more precisely.200 divided by 470:200 ÷ 470 = 20/47 ≈ 0.4255319149.So, 0.4255319149.Initial diversity ratio: 0.35.Change: 0.4255319149 - 0.35 = 0.0755319149.Percentage change: (0.0755319149 / 0.35) * 100 ≈ (0.0755319149 / 0.35) * 100.Compute 0.0755319149 ÷ 0.35:0.0755319149 ÷ 0.35 ≈ 0.2157.Multiply by 100: ≈21.57%.So, approximately 21.57% increase.Therefore, the new diversity ratio is approximately 0.4255, and the percentage change is approximately 21.57%.But let me express it as a fraction.200/470 simplifies to 20/47, which is approximately 0.4255.So, the new diversity ratio is 20/47, and the percentage change is (20/47 - 0.35)/0.35 *100.Wait, 0.35 is 7/20.So, (20/47 - 7/20)/ (7/20) *100.Compute 20/47 - 7/20:Find a common denominator, which is 940.20/47 = 400/9407/20 = 329/940So, 400/940 - 329/940 = 71/940So, (71/940) / (7/20) = (71/940) * (20/7) = (71*20)/(940*7) = 1420/6580 = Simplify:Divide numerator and denominator by 10: 142/658Divide numerator and denominator by 2: 71/32971 and 329: 329 ÷ 71 = 4.633, not an integer. So, 71/329 is the simplified fraction.So, 71/329 ≈0.2157, which is 21.57%.So, the percentage change is 71/329, which is approximately 21.57%.Therefore, the new diversity ratio is 20/47, and the percentage change is approximately 21.57%.So, summarizing:1. The multiplier m is 200/190 = 20/19 ≈1.0526.2. The new diversity ratio is 20/47≈0.4255, and the percentage change is approximately 21.57%.Therefore, the answers are:1. m = 20/19 or approximately 1.0526.2. New diversity ratio: 20/47≈0.4255, percentage change≈21.57%.But let me express the percentage change as a fraction.71/329 is approximately 0.2157, which is 21.57%.Alternatively, to express it as a fraction, 71/329 can be simplified?Wait, 71 is a prime number. 329 ÷71=4.633, which is not an integer. So, 71/329 is the simplest form.But perhaps we can write it as a percentage with two decimal places: 21.57%.Alternatively, if we want to be precise, 71/329≈0.2157, so 21.57%.So, the percentage change is approximately 21.57%.Therefore, the answers are:1. m = 20/19 ≈1.0526.2. New diversity ratio: 20/47≈0.4255, percentage change≈21.57%.But let me check if the initial diversity ratio is 0.35, which is 35/100=7/20.So, 7/20=0.35.After applying m, it's 200/470=20/47≈0.4255.So, the change is 20/47 - 7/20= (400 - 329)/940=71/940.So, 71/940 divided by 7/20 is (71/940)*(20/7)= (71*20)/(940*7)=1420/6580=71/329≈0.2157.So, yes, 21.57%.Therefore, the answers are:1. m=20/19≈1.0526.2. New diversity ratio=20/47≈0.4255, percentage change≈21.57%.I think that's it.</think>