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❓:A project manager, Alex, recognizes the potential of an engineer, Taylor, and assigns Taylor as a mentor for new recruits. The company is initiating a new project that requires the allocation of resources in an optimal way to minimize cost and maximize efficiency. Taylor is responsible for mentoring the recruits in applying advanced mathematical techniques to solve the following problem:1. The project has 3 tasks (T1, T2, T3) that need to be completed. Each task requires different amounts of time and resources. The time (in hours) and cost (in dollars) for each task are given by: - T1: ( t_1 = 3x + 2y ), ( c_1 = 4x + y ) - T2: ( t_2 = 5x + y ), ( c_2 = 2x + 3y ) - T3: ( t_3 = 6x + 3y ), ( c_3 = x + 4y ) Taylor needs to determine the values of ( x ) and ( y ) that minimize the total cost ( C = c_1 + c_2 + c_3 ) while ensuring that the total time ( T = t_1 + t_2 + t_3 ) does not exceed a maximum threshold of 40 hours. Formulate the optimization problem and find the values of ( x ) and ( y ).2. After determining the optimal values of ( x ) and ( y ), Taylor needs to mentor the recruits on how to allocate the resources to the tasks. Suppose the company has a budget of 1000 for the project. Determine if the budget is sufficient given the cost ( C ) calculated from the optimal values of ( x ) and ( y ). If the budget is insufficient, calculate the additional amount required.
🧠:<think>Alright, so I have this optimization problem to solve, and I need to figure out the best way to approach it. Let me start by understanding the problem step by step.First, there are three tasks: T1, T2, and T3. Each task has its own time and cost equations in terms of variables x and y. The goal is to find the values of x and y that minimize the total cost C, which is the sum of the costs of all three tasks. At the same time, the total time T, which is the sum of the times for all three tasks, must not exceed 40 hours. After finding these optimal x and y, I also need to check if the total cost stays within a 1000 budget. If not, I have to calculate how much more money is needed.Okay, let me write down the given equations to make it clearer.For each task:- T1: Time ( t_1 = 3x + 2y ), Cost ( c_1 = 4x + y )- T2: Time ( t_2 = 5x + y ), Cost ( c_2 = 2x + 3y )- T3: Time ( t_3 = 6x + 3y ), Cost ( c_3 = x + 4y )Total time ( T = t_1 + t_2 + t_3 )Total cost ( C = c_1 + c_2 + c_3 )So, let me compute the total time and total cost by adding up the respective components.Calculating total time:( T = (3x + 2y) + (5x + y) + (6x + 3y) )Let me combine like terms:- x terms: 3x + 5x + 6x = 14x- y terms: 2y + y + 3y = 6ySo, ( T = 14x + 6y )Similarly, calculating total cost:( C = (4x + y) + (2x + 3y) + (x + 4y) )Again, combining like terms:- x terms: 4x + 2x + x = 7x- y terms: y + 3y + 4y = 8ySo, ( C = 7x + 8y )Alright, so now the problem is to minimize ( C = 7x + 8y ) subject to the constraint ( 14x + 6y leq 40 ). I assume that x and y are non-negative since they represent resources, which can't be negative.So, this is a linear programming problem. The objective function is linear, and the constraint is also linear. To solve this, I can use the graphical method since there are only two variables, x and y.First, let me write down the problem formally:Minimize ( C = 7x + 8y )Subject to:( 14x + 6y leq 40 )( x geq 0 )( y geq 0 )I can also note that the feasible region is defined by these inequalities, and the minimum will occur at one of the corner points of this region.So, to find the feasible region, I need to graph the constraint ( 14x + 6y = 40 ) and identify the region where ( 14x + 6y leq 40 ).Let me find the intercepts of the line ( 14x + 6y = 40 ).When x = 0:( 6y = 40 ) => ( y = 40/6 ≈ 6.6667 )When y = 0:( 14x = 40 ) => ( x = 40/14 ≈ 2.8571 )So, the line passes through (0, 6.6667) and (2.8571, 0). The feasible region is below this line in the first quadrant.Now, the corner points of the feasible region are:1. (0, 0)2. (0, 6.6667)3. (2.8571, 0)But wait, actually, in linear programming, the feasible region is a polygon bounded by these lines and the axes. So, the corner points are indeed these three points.However, sometimes, if there are multiple constraints, the feasible region can have more corner points, but in this case, since we only have one inequality constraint besides x and y being non-negative, the feasible region is a triangle with these three vertices.So, to find the minimum of C, I need to evaluate C at each of these corner points.Let's compute C at each point.1. At (0, 0):( C = 7*0 + 8*0 = 0 )But wait, can x and y be zero? If x and y are zero, then all tasks would take zero time and cost zero. But in reality, is that feasible? Because if x and y are zero, then the tasks can't be completed. So, perhaps, the problem assumes that x and y are positive? Or maybe the constraints are such that x and y can be zero.Wait, the problem says "the company is initiating a new project that requires the allocation of resources in an optimal way to minimize cost and maximize efficiency." So, perhaps, it's allowed for x and y to be zero if that minimizes the cost, but we have to ensure that the total time is within 40 hours.But if x and y are zero, the total time is zero, which is within the limit, but the cost is also zero. However, in reality, you can't have zero resources if you need to complete the tasks. So, maybe there's a misunderstanding here.Wait, looking back at the problem statement: "the total time T = t1 + t2 + t3 does not exceed a maximum threshold of 40 hours." So, T must be <= 40. If x and y are zero, T is zero, which is within the limit. So, technically, (0,0) is a feasible point, but it results in zero cost. But that seems counterintuitive because you can't complete the tasks with zero resources.Wait, perhaps the tasks require a certain minimum amount of resources? Or maybe the equations for t1, t2, t3 are such that x and y can't be zero because otherwise, the tasks can't be completed. Hmm, the problem doesn't specify that x and y have to be positive, just that they are variables. So, mathematically, (0,0) is a feasible point with cost zero. But that might not make practical sense.Alternatively, maybe the problem expects x and y to be positive, but the constraints don't specify that. Hmm, this is a bit confusing.Wait, let's see. If x and y are zero, the total time is zero, which is within the 40-hour limit, but the total cost is zero, which is the minimum possible. So, from a purely mathematical standpoint, the minimum cost is zero at (0,0). But that doesn't make sense in the context of the problem because you can't complete the tasks without resources.Therefore, perhaps the problem expects that x and y must be such that the tasks are actually completed, meaning that x and y can't be zero. But the problem doesn't specify that. Hmm.Alternatively, maybe I misinterpreted the problem. Let me reread it."Taylor needs to determine the values of x and y that minimize the total cost C = c1 + c2 + c3 while ensuring that the total time T = t1 + t2 + t3 does not exceed a maximum threshold of 40 hours."So, the only constraint is T <= 40. There's no constraint that the tasks must be completed, just that the total time doesn't exceed 40. So, if x and y are zero, the tasks take zero time, which is within the limit, but the cost is zero.But in reality, the company wouldn't assign zero resources because then the project wouldn't be completed. So, maybe the problem expects that x and y are positive, but it's not stated. Hmm.Alternatively, perhaps the problem is intended to have x and y as positive variables, so we can ignore the (0,0) point as a trivial solution.But in linear programming, the feasible region includes all points satisfying the constraints, including (0,0). So, unless the problem specifies that x and y must be positive, we have to consider (0,0) as a feasible point.But since the problem is about resource allocation to complete the project, I think it's safe to assume that x and y must be positive. So, maybe the feasible region is the area where x >= 0, y >= 0, and 14x + 6y <= 40, but excluding (0,0). However, in linear programming, the minimum can still occur at (0,0), but in this context, it's not practical.Alternatively, perhaps the problem expects that the tasks must be completed, meaning that T must be at least some positive value, but the problem only specifies an upper bound, not a lower bound.Hmm, this is a bit of a conundrum. Maybe I should proceed with the mathematical solution, considering all feasible points, including (0,0), and then discuss the practical implications.So, evaluating C at the three corner points:1. (0, 0): C = 02. (0, 6.6667): C = 7*0 + 8*(40/6) = 0 + 8*(6.6667) ≈ 53.33333. (2.8571, 0): C = 7*(40/14) + 8*0 ≈ 7*2.8571 ≈ 20So, comparing these, the minimum cost is 0 at (0,0), followed by approximately 20 at (2.8571, 0), and approximately 53.3333 at (0, 6.6667).But as I thought earlier, (0,0) is a trivial solution where no resources are allocated, resulting in zero cost but also zero time. Since the problem is about completing the project, perhaps we need to consider only the non-trivial solutions where x and y are positive, but the problem doesn't specify that.Alternatively, maybe I made a mistake in interpreting the problem. Let me check the equations again.Wait, the time equations are given as:- T1: ( t_1 = 3x + 2y )- T2: ( t_2 = 5x + y )- T3: ( t_3 = 6x + 3y )So, if x and y are zero, all tasks take zero time, which is within the 40-hour limit, but the project isn't actually completed. So, perhaps the problem expects that the tasks are completed, meaning that x and y must be such that each task's time is positive. But the problem doesn't specify that.Alternatively, maybe the problem is intended to have x and y as positive variables, so we can ignore the (0,0) point. In that case, the minimum cost would be at (2.8571, 0), which is approximately 20.But let me think again. If x and y can be zero, then the minimum cost is zero, but that's not practical. So, perhaps the problem expects us to find the minimum positive cost, which would be at (2.8571, 0). Alternatively, maybe the problem expects us to consider that both x and y must be positive, so the minimum occurs somewhere along the line between (0, 6.6667) and (2.8571, 0). But in linear programming, the minimum occurs at the vertices, not along the edges.Wait, but in this case, the objective function is ( C = 7x + 8y ). The gradient of this function is (7,8), which points in the direction of increasing C. So, to minimize C, we want to go in the opposite direction, towards the origin.But since the feasible region is a triangle with vertices at (0,0), (0, 6.6667), and (2.8571, 0), the point closest to the origin is (0,0), which gives the minimum C. However, as discussed, this might not be practical.Alternatively, perhaps the problem expects us to consider that x and y must be positive, so we have to find the minimum in the interior of the feasible region, but in linear programming, the minimum occurs at the vertices.Wait, unless there are more constraints, but the problem only gives one inequality constraint: ( 14x + 6y leq 40 ), and x, y >= 0.So, unless there's a lower bound on x and y, the minimum is at (0,0). But that seems odd.Alternatively, maybe I misread the problem, and the tasks require a certain minimum time, but the problem only specifies a maximum.Wait, the problem says: "the total time T = t1 + t2 + t3 does not exceed a maximum threshold of 40 hours." So, it's only an upper bound, not a lower bound.Therefore, mathematically, the minimum cost is achieved at (0,0), but in practice, that's not feasible. So, perhaps the problem expects us to assume that x and y are positive, and thus, the minimum occurs at (2.8571, 0), which is approximately 2.8571 for x and 0 for y, giving a total cost of approximately 20.But let me check if that's the case.Wait, if x = 40/14 ≈ 2.8571 and y = 0, then T = 14x + 6y = 14*(40/14) + 0 = 40, which is exactly the maximum allowed time. So, that point is on the boundary of the feasible region.Similarly, if y is 40/6 ≈ 6.6667 and x = 0, T = 0 + 6*(40/6) = 40.So, both points (2.8571, 0) and (0, 6.6667) are on the boundary where T = 40.Now, evaluating C at these two points:At (2.8571, 0): C = 7*(40/14) + 8*0 = 7*(2.8571) ≈ 20At (0, 6.6667): C = 0 + 8*(40/6) ≈ 53.3333So, clearly, (2.8571, 0) gives a lower cost.But again, if x = 2.8571 and y = 0, then the time for each task is:T1: 3x + 2y = 3*(2.8571) + 0 ≈ 8.5713 hoursT2: 5x + y = 5*(2.8571) + 0 ≈ 14.2855 hoursT3: 6x + 3y = 6*(2.8571) + 0 ≈ 17.1426 hoursTotal time: 8.5713 + 14.2855 + 17.1426 ≈ 39.9994 hours, which is approximately 40 hours.So, that works.But if y = 0, does that mean that we're not using resource y at all? That might be the case, but mathematically, it's allowed.Alternatively, maybe the problem expects both x and y to be positive, but since the problem doesn't specify, we have to go with the mathematical solution.Therefore, the minimum cost is achieved at (2.8571, 0), with a total cost of approximately 20.But wait, let me double-check my calculations.Total cost C = 7x + 8yAt x = 40/14 ≈ 2.8571, y = 0:C = 7*(40/14) = (7*40)/14 = 280/14 = 20Yes, that's correct.Similarly, at y = 40/6 ≈ 6.6667, x = 0:C = 8*(40/6) = 320/6 ≈ 53.3333So, the minimum is indeed at (2.8571, 0).But let me think again about the practicality. If y = 0, then for T1, the time is 3x, for T2, it's 5x, and for T3, it's 6x. So, all tasks are being completed using only resource x. Is that acceptable? The problem doesn't specify any constraints on x and y other than the total time, so I think it is.Therefore, the optimal solution is x = 40/14 ≈ 2.8571 and y = 0, with a total cost of 20.But wait, 40/14 simplifies to 20/7, which is approximately 2.8571. So, x = 20/7, y = 0.So, in exact terms, x = 20/7, y = 0.Now, moving on to part 2: The company has a budget of 1000. Is the budget sufficient given the cost C calculated from the optimal values of x and y?Well, the total cost C is 20, which is way below 1000. So, the budget is more than sufficient. In fact, the company could potentially increase x and y to use more resources, but since we're minimizing cost, we've already found the minimum possible cost.But wait, let me make sure. If the budget is 1000, and the minimum cost is 20, then the budget is more than enough. The company could even choose to allocate more resources, but that would increase the cost beyond 20, but since we're minimizing, we don't need to do that.Alternatively, if the problem had a lower budget, say, less than 20, then we would have to say it's insufficient and calculate the additional amount required. But in this case, 1000 is way more than 20.So, summarizing:1. The optimal values are x = 20/7 ≈ 2.8571 and y = 0, resulting in a total cost of 20.2. The budget of 1000 is more than sufficient, as the required cost is only 20.But wait, let me check if I made a mistake in interpreting the problem. Maybe the tasks require a certain minimum time, but the problem only specifies a maximum. So, if we set x and y to zero, the time is zero, which is within the limit, but the cost is zero. However, in reality, you can't complete the tasks with zero resources, so perhaps the problem expects that x and y must be such that each task's time is positive, but the problem doesn't specify that.Alternatively, maybe the problem expects that the tasks must be completed, meaning that the total time must be at least some positive value, but the problem only gives an upper bound. So, without a lower bound, the minimum cost is zero.But since the problem is about resource allocation to minimize cost while not exceeding time, and given that the company has a budget, I think the intended solution is to find the minimum cost given the time constraint, which is 20, and then check if the budget is sufficient.Therefore, the budget is sufficient, and no additional amount is required.But just to be thorough, let me consider if there's another way to interpret the problem. Maybe the tasks have to be completed, meaning that the time can't be zero, so x and y can't be zero. In that case, we have to find the minimum cost where x and y are positive.But in linear programming, without a lower bound on x and y, the minimum is still at (0,0). So, unless the problem specifies that x and y must be positive, we can't assume that.Alternatively, maybe the problem expects us to consider that both x and y must be positive, so we have to find the minimum in the interior of the feasible region. But in linear programming, the minimum occurs at the vertices, not in the interior.Wait, unless the objective function is such that it's minimized along an edge, but in this case, the objective function is 7x + 8y, which is minimized at (0,0).So, unless there's a constraint that x and y must be positive, the minimum is at (0,0). But since the problem is about resource allocation for a project, it's implied that resources are needed, so x and y must be positive. Therefore, perhaps the problem expects us to consider only positive x and y, and thus, the minimum occurs at (20/7, 0), as we found earlier.Alternatively, maybe the problem expects us to consider that both x and y must be positive, so we have to find the minimum in the interior of the feasible region. But in linear programming, the minimum occurs at the vertices, not in the interior.Wait, unless the objective function is such that it's minimized along an edge, but in this case, the objective function is 7x + 8y, which is minimized at (0,0).So, perhaps the problem expects us to consider that x and y are positive, but without a lower bound, the minimum is still at (20/7, 0), as that's the point where the objective function is minimized while keeping T = 40.Therefore, I think the correct answer is x = 20/7, y = 0, with a total cost of 20, and the budget is sufficient.But just to be absolutely sure, let me check the calculations again.Total time T = 14x + 6yAt x = 20/7, y = 0:T = 14*(20/7) + 0 = 14*(20/7) = 2*20 = 40 hours, which is exactly the maximum allowed.Total cost C = 7x + 8y = 7*(20/7) + 0 = 20 + 0 = 20.Yes, that's correct.Therefore, the optimal solution is x = 20/7, y = 0, with a total cost of 20, which is well within the 1000 budget.</think>
❓:A young classical music student in Hong Kong is preparing for a piano recital. She practices two different compositions, one by Chopin and the other by Beethoven. 1. She notices that she can master one page of Chopin's composition in 3 hours and one page of Beethoven's composition in 4 hours. If she has a total of 60 hours to practice and the total number of pages she wants to master is 20, how many pages of each composition should she practice to utilize her time most efficiently while mastering exactly 20 pages?2. During her practice, she also records the number of mistakes she makes per page. For Chopin's composition, the number of mistakes she makes per page follows a Poisson distribution with a mean of 2 mistakes per page, and for Beethoven's composition, it follows a Poisson distribution with a mean of 1 mistake per page. What is the probability that she makes fewer than 5 mistakes while practicing 2 random pages from each composition?
🧠:<think>Alright, so I have this problem about a classical music student in Hong Kong preparing for a piano recital. She's practicing two compositions: one by Chopin and one by Beethoven. There are two parts to the problem. Let me tackle them one by one.Starting with the first part:1. She can master one page of Chopin in 3 hours and one page of Beethoven in 4 hours. She has a total of 60 hours to practice and wants to master exactly 20 pages. I need to figure out how many pages of each composition she should practice to use her time most efficiently.Hmm, okay. So, this seems like a system of equations problem. Let me define variables:Let x = number of Chopin pages she practices.Let y = number of Beethoven pages she practices.We know two things:1. The total number of pages is 20, so x + y = 20.2. The total time spent is 60 hours. Since each Chopin page takes 3 hours and each Beethoven page takes 4 hours, the total time is 3x + 4y = 60.So, we have the system:x + y = 20 3x + 4y = 60I can solve this using substitution or elimination. Let me use substitution.From the first equation, x = 20 - y.Substitute into the second equation:3(20 - y) + 4y = 60 60 - 3y + 4y = 60 60 + y = 60 y = 0Wait, y = 0? That means she should practice 0 pages of Beethoven and 20 pages of Chopin? Let me check that.If y = 0, then x = 20.Time spent: 3*20 + 4*0 = 60 hours. That works. So, she can practice 20 pages of Chopin in 60 hours.But is that the most efficient? Hmm, efficiency in terms of pages per hour. Let me think.Chopin: 1 page per 3 hours, so 1/3 pages per hour. Beethoven: 1 page per 4 hours, so 1/4 pages per hour.So, Chopin is more efficient in terms of pages per hour. Therefore, to maximize the number of pages, she should focus on Chopin. But wait, she already wants to master exactly 20 pages. Since she can do 20 pages of Chopin in 60 hours, which is exactly her time limit, that seems optimal.Alternatively, if she tried to do some Beethoven, she would have to do fewer pages because Beethoven takes longer per page. So, yes, 20 Chopin pages and 0 Beethoven pages would utilize her time most efficiently.Wait, but the problem says "utilize her time most efficiently while mastering exactly 20 pages." So, since she must master exactly 20 pages, and she can do all Chopin, which takes exactly 60 hours, that's the most efficient way.So, the answer is 20 pages of Chopin and 0 pages of Beethoven.But let me double-check. Suppose she does 19 Chopin and 1 Beethoven.Time: 19*3 + 1*4 = 57 + 4 = 61 hours. That's over her limit.If she does 18 Chopin and 2 Beethoven: 18*3 + 2*4 = 54 + 8 = 62 hours. Still over.Wait, but if she does 16 Chopin and 4 Beethoven: 16*3 + 4*4 = 48 + 16 = 64 hours. Still over.Wait, maybe I need to find the maximum number of pages within 60 hours, but she wants exactly 20 pages. So, the only way to get exactly 20 pages is to do 20 Chopin, which takes exactly 60 hours.Alternatively, if she does some Beethoven, she would have to reduce the number of Chopin pages, but since she needs exactly 20, she can't do that. Wait, no, she can do a combination where x + y = 20, but the time must be <=60.But in this case, x + y =20, and 3x +4y=60.So, solving gives y=0, x=20.Therefore, she must do 20 Chopin pages.Okay, that seems correct.Now, moving on to the second part:2. She records the number of mistakes per page. For Chopin, it's Poisson with mean 2 per page. For Beethoven, Poisson with mean 1 per page. What's the probability that she makes fewer than 5 mistakes while practicing 2 random pages from each composition?So, she practices 2 pages of Chopin and 2 pages of Beethoven. Each Chopin page has Poisson(2) mistakes, and each Beethoven page has Poisson(1) mistakes.We need the probability that the total number of mistakes is fewer than 5.First, let's model the total mistakes.Let X be the number of mistakes on Chopin pages. Since she practices 2 pages, each with Poisson(2) mistakes, the total X ~ Poisson(2*2) = Poisson(4).Similarly, let Y be the number of mistakes on Beethoven pages. She practices 2 pages, each with Poisson(1) mistakes, so Y ~ Poisson(2).Since X and Y are independent, the total mistakes Z = X + Y ~ Poisson(4 + 2) = Poisson(6).Wait, is that correct? The sum of independent Poisson variables is Poisson with parameter equal to the sum of the individual parameters. So, yes, Z ~ Poisson(6).We need P(Z < 5) = P(Z ≤ 4).The Poisson probability mass function is P(Z = k) = (e^{-λ} * λ^k) / k!So, we can compute P(Z ≤ 4) = sum_{k=0}^4 P(Z = k).Let me compute each term:λ = 6.P(Z=0) = e^{-6} * 6^0 / 0! = e^{-6} ≈ 0.002478752P(Z=1) = e^{-6} * 6^1 / 1! = 6e^{-6} ≈ 0.014872513P(Z=2) = e^{-6} * 6^2 / 2! = (36/2)e^{-6} = 18e^{-6} ≈ 0.044617538P(Z=3) = e^{-6} * 6^3 / 3! = (216/6)e^{-6} = 36e^{-6} ≈ 0.089235077P(Z=4) = e^{-6} * 6^4 / 4! = (1296/24)e^{-6} = 54e^{-6} ≈ 0.133852615Now, sum these up:0.002478752 + 0.014872513 = 0.017351265+ 0.044617538 = 0.061968803+ 0.089235077 = 0.15120388+ 0.133852615 = 0.285056495So, approximately 0.285056495.But let me compute it more accurately using exact fractions.Alternatively, I can use the cumulative distribution function for Poisson(6) at 4.Alternatively, using a calculator or table, but since I don't have one, I'll compute it step by step.Compute each term precisely:Compute e^{-6} ≈ 0.002478752176666358Compute P(Z=0): 0.002478752176666358P(Z=1): 6 * e^{-6} ≈ 0.014872513059998148P(Z=2): (6^2 / 2!) e^{-6} = (36 / 2) e^{-6} = 18 e^{-6} ≈ 0.04461753917999444P(Z=3): (6^3 / 3!) e^{-6} = (216 / 6) e^{-6} = 36 e^{-6} ≈ 0.08923507835998888P(Z=4): (6^4 / 4!) e^{-6} = (1296 / 24) e^{-6} = 54 e^{-6} ≈ 0.13385261503998334Now, sum them:0.002478752176666358 + 0.014872513059998148 = 0.017351265236664506 + 0.04461753917999444 = 0.06196880441665895 + 0.08923507835998888 = 0.15120388277664783 + 0.13385261503998334 = 0.28505649781663117So, approximately 0.285056, which is about 28.5056%.Therefore, the probability is approximately 28.51%.But let me check if I did everything correctly.Wait, she practices 2 pages from each composition. So, for Chopin, 2 pages, each Poisson(2), so total X ~ Poisson(4). For Beethoven, 2 pages, each Poisson(1), so Y ~ Poisson(2). Then, Z = X + Y ~ Poisson(6). That seems correct.Yes, because the sum of independent Poisson variables is Poisson with parameter equal to the sum.So, Z ~ Poisson(6), and we need P(Z < 5) = P(Z ≤ 4).Yes, that's correct.So, the probability is approximately 28.51%.I think that's the answer.Final Answer1. She should practice boxed{20} pages of Chopin and boxed{0} pages of Beethoven.2. The probability is boxed{0.2851}.</think>
❓:Math problem:John, a family man who loves home improvement and regularly watches HGTV, decides to renovate his kitchen. He wants to install new tiles on the floor and add a custom kitchen island. The kitchen floor has a rectangular shape measuring 12 feet by 15 feet. He wants to use hexagonal tiles, each with a side length of 6 inches. 1. Calculate the number of hexagonal tiles John will need to cover the entire kitchen floor, considering the hexagonal packing arrangement where each hexagon is surrounded by six others. Assume there is no waste or cutting of tiles.2. John also plans to build a custom kitchen island in the shape of a regular octagon. The island's diameter (distance between two opposite vertices) is 6 feet. Calculate the area of the octagon and determine how much material (in square feet) is needed to cover the top surface of the island if he chooses to use a granite slab.
🧠:<think>Okay, so I have this math problem about John renovating his kitchen. He wants to put hexagonal tiles on the floor and build a custom kitchen island that's a regular octagon. I need to figure out how many tiles he needs and the area of the octagon. Hmm, let me take this step by step.First, the kitchen floor is 12 feet by 15 feet. That's a rectangle, so the area is straightforward. I can calculate that by multiplying length and width. But he's using hexagonal tiles, each with a side length of 6 inches. Wait, 6 inches is half a foot, so maybe I should convert everything to feet to keep the units consistent.So, the kitchen area is 12 ft * 15 ft = 180 square feet. Each hexagonal tile has a side length of 0.5 feet. I remember that the area of a regular hexagon can be calculated with the formula: (3√3 / 2) * s², where s is the side length. Let me plug in 0.5 feet for s.Calculating the area of one tile: (3√3 / 2) * (0.5)². Let me compute that. First, (0.5)² is 0.25. Then, 3√3 is approximately 3 * 1.732 = 5.196. So, 5.196 / 2 is about 2.598. Multiply that by 0.25: 2.598 * 0.25 ≈ 0.6495 square feet per tile.Now, to find the number of tiles needed, I can divide the total kitchen area by the area of one tile. So, 180 / 0.6495 ≈ 277. So, John would need approximately 277 hexagonal tiles. But wait, the problem mentions hexagonal packing arrangement. I think that's the most efficient way to pack hexagons, which covers about 90.69% of the area. Hmm, does that affect the number of tiles?Wait, no, because the formula for the area of the hexagon already accounts for the space it occupies. So, if we calculate the number of tiles based on area, it should be fine. But maybe I should double-check. Alternatively, sometimes people calculate the number of tiles based on the area divided by the tile's area, regardless of packing. Since the problem says to assume no waste or cutting, maybe it's just a straightforward division. So, 180 / 0.6495 ≈ 277. So, I think that's the answer for part 1.Moving on to part 2: the kitchen island is a regular octagon with a diameter of 6 feet. The diameter is the distance between two opposite vertices. I need to find the area of this octagon.I remember that the area of a regular octagon can be calculated if you know the length of a side or the radius (distance from center to a vertex). Since the diameter is given as 6 feet, the radius (r) is half of that, so 3 feet.The formula for the area of a regular octagon is 2(1 + √2) * s², where s is the side length. But I don't have the side length; I have the radius. So, I need to relate the radius to the side length.In a regular octagon, the radius (distance from center to a vertex) is related to the side length (s) by the formula: r = s / (2 * sin(π/8)). Let me compute sin(π/8). π/8 is 22.5 degrees. The sine of 22.5 degrees is approximately 0.38268. So, r = s / (2 * 0.38268) ≈ s / 0.76536. Therefore, s ≈ r * 0.76536.Given that r is 3 feet, s ≈ 3 * 0.76536 ≈ 2.296 feet. So, the side length is approximately 2.296 feet.Now, plugging this into the area formula: 2(1 + √2) * (2.296)². Let's compute this step by step.First, calculate (2.296)²: 2.296 * 2.296 ≈ 5.271 square feet.Next, compute 2(1 + √2). √2 is approximately 1.4142, so 1 + √2 ≈ 2.4142. Multiply by 2: 2 * 2.4142 ≈ 4.8284.Now, multiply 4.8284 by 5.271: 4.8284 * 5.271 ≈ 25.45 square feet.Wait, that seems a bit low. Let me double-check my steps.Alternatively, maybe there's a different formula for the area of a regular octagon when given the radius. I think another formula is 2 * (1 + √2) * r². Let me check that.If that's the case, then the area would be 2*(1 + √2)*(3)² = 2*(1 + 1.4142)*9 = 2*(2.4142)*9 ≈ 4.8284 * 9 ≈ 43.456 square feet. That seems more reasonable.Wait, so which formula is correct? I think I might have confused the formulas. Let me verify.The area of a regular polygon can be calculated as (1/2) * perimeter * apothem. For an octagon, the apothem (a) is the distance from the center to the midpoint of a side. The apothem can be related to the radius (r) by the formula: a = r * cos(π/8). Since the octagon has 8 sides, each central angle is 45 degrees, so half of that is 22.5 degrees, which is π/8 radians.So, a = r * cos(π/8). cos(π/8) is approximately 0.92388. So, a ≈ 3 * 0.92388 ≈ 2.7716 feet.The perimeter of the octagon is 8 * s. We found earlier that s ≈ 2.296 feet, so perimeter ≈ 8 * 2.296 ≈ 18.368 feet.Then, area = (1/2) * perimeter * apothem ≈ 0.5 * 18.368 * 2.7716 ≈ 0.5 * 50.83 ≈ 25.415 square feet. Hmm, that's close to my first calculation but not the same as the second.Wait, so now I'm confused because using the radius directly in the area formula gave me 43.456, but using the apothem and perimeter gave me 25.415. Which one is correct?I think I made a mistake in the first formula. The formula 2*(1 + √2)*r² is actually for the area when the radius is the distance from the center to a vertex, which is correct. But let me compute that again.2*(1 + √2)*(3)^2 = 2*(1 + 1.4142)*9 = 2*(2.4142)*9 ≈ 4.8284*9 ≈ 43.456 square feet.But when I calculated using the apothem and perimeter, I got 25.415. These two results are conflicting. There must be a mistake in one of the methods.Wait, let me check the formula for the area in terms of the radius. Maybe I got it wrong. The formula for the area of a regular polygon is (1/2) * n * r² * sin(2π/n), where n is the number of sides. For an octagon, n=8.So, plugging in: (1/2)*8*(3)^2*sin(2π/8) = 4*9*sin(π/4) = 36*(√2/2) = 36*(0.7071) ≈ 25.456 square feet. Okay, so that's consistent with the apothem method.So, the correct area is approximately 25.456 square feet. Therefore, the area is about 25.46 square feet.Wait, so why did the formula 2*(1 + √2)*r² give me 43.456? Maybe that formula is incorrect or uses a different definition. Let me check online.Wait, I can't actually check online, but I recall that the formula 2*(1 + √2)*s² is for the area when s is the side length. So, if I have the side length, I can use that. But if I have the radius, I need to use a different formula.So, perhaps the formula 2*(1 + √2)*r² is incorrect. Instead, the correct formula using the radius is (1/2)*n*r²*sin(2π/n). For n=8, that's (1/2)*8*r²*sin(π/4) = 4*r²*(√2/2) = 2√2*r².So, plugging in r=3: 2√2*(3)^2 = 2√2*9 = 18√2 ≈ 18*1.4142 ≈ 25.456 square feet. That's consistent with the other method.So, the area is approximately 25.46 square feet. Therefore, John needs about 25.46 square feet of granite slab for the kitchen island.Wait, but earlier when I calculated using the side length, I got 25.456, which is the same as this. So, that must be the correct answer.So, summarizing:1. Kitchen floor area: 12*15=180 sq ft.Area of one hexagonal tile: (3√3/2)*(0.5)^2 ≈ 0.6495 sq ft.Number of tiles: 180 / 0.6495 ≈ 277 tiles.2. Kitchen island area: 25.46 sq ft.I think that's it.</think>
❓:Giovanni, a middle-aged Italian man, is a passionate fan of soap operas and drama shows. He decides to analyze the airing patterns of his favorite shows to optimize his viewing schedule. He notices that each soap opera episode has a unique emotional intensity score ( I ), which is a function of time ( t ) (in minutes) since the episode started. The intensity score is given by the function ( I(t) = 5t^2 - 2t + 3 ).1. Giovanni wants to find the total emotional impact of a single episode by integrating the intensity score over the duration of the episode, which lasts 60 minutes. Calculate the total emotional impact by evaluating the definite integral of ( I(t) ) from ( t = 0 ) to ( t = 60 ).2. Giovanni observes that the emotional intensity scores of two different episodes can interact with each other when watched consecutively. If he watches two episodes back-to-back, the total combined emotional intensity score is given by the product of their individual intensity scores at any time ( t ). Given that the second episode starts immediately after the first one ends, find the maximum combined intensity score ( I_1(t) cdot I_2(t-60) ) over the interval from ( t = 60 ) to ( t = 120 ), where ( I_1(t) ) and ( I_2(t-60) ) are the intensity scores of the first and second episodes, respectively.
🧠:<think>Okay, so I have these two calculus problems to solve related to Giovanni analyzing his soap opera episodes. Let me take them one at a time.Starting with the first problem: Giovanni wants to find the total emotional impact of a single episode by integrating the intensity score over 60 minutes. The intensity score is given by I(t) = 5t² - 2t + 3. So, I need to compute the definite integral of I(t) from t = 0 to t = 60.Alright, integrating a polynomial function. I remember that the integral of t^n is (t^(n+1))/(n+1). So, let's break it down term by term.First, the integral of 5t². The integral of t² is (t³)/3, so multiplying by 5 gives (5/3)t³.Next, the integral of -2t. The integral of t is (t²)/2, so multiplying by -2 gives -t².Then, the integral of 3. The integral of a constant is 3t.Putting it all together, the antiderivative F(t) is (5/3)t³ - t² + 3t.Now, I need to evaluate this from 0 to 60. So, F(60) - F(0).Calculating F(60):First term: (5/3)*(60)³. Let's compute 60³ first. 60*60=3600, 3600*60=216000. So, (5/3)*216000. Let's compute 216000 divided by 3 is 72000, then multiplied by 5 is 360000.Second term: -(60)². 60*60=3600, so it's -3600.Third term: 3*60=180.So, F(60) = 360000 - 3600 + 180.Let me compute that step by step:360000 - 3600 = 356400356400 + 180 = 356580Now, F(0) is just plugging in t=0 into the antiderivative:(5/3)*(0)³ - (0)² + 3*(0) = 0 - 0 + 0 = 0Therefore, the definite integral from 0 to 60 is 356580 - 0 = 356580.Hmm, that seems straightforward. Let me just double-check my calculations.First term: 5/3 * 60³. 60³ is 216000, 216000 * 5 = 1,080,000, divided by 3 is 360,000. Correct.Second term: -60² = -3600. Correct.Third term: 3*60=180. Correct.Adding them up: 360,000 - 3,600 = 356,400; 356,400 + 180 = 356,580. Yep, that's right.So, the total emotional impact is 356,580.Moving on to the second problem: Giovanni watches two episodes back-to-back, and the combined intensity is the product of their individual intensity scores at any time t. The second episode starts immediately after the first one ends, so for t between 60 and 120, the first episode's intensity is I1(t) = 5t² - 2t + 3, but wait, actually, the first episode only lasts until t=60. So, after t=60, the first episode has ended, and the second episode is playing.Wait, hold on. The problem says: "the total combined emotional intensity score is given by the product of their individual intensity scores at any time t." So, for t between 60 and 120, I1(t) is the intensity of the first episode, but the first episode has already ended at t=60. Hmm, that doesn't make sense because the first episode's intensity would be zero after t=60.Wait, maybe I misinterpret. Let me read again."the total combined emotional intensity score is given by the product of their individual intensity scores at any time t. Given that the second episode starts immediately after the first one ends, find the maximum combined intensity score I1(t) ⋅ I2(t−60) over the interval from t = 60 to t = 120."Ah, okay, so for t between 60 and 120, the first episode is still being watched? Wait, no. The first episode is from t=0 to t=60, and the second episode is from t=60 to t=120. So, at any time t between 60 and 120, the first episode has already ended, so I1(t) would be zero, and I2(t−60) would be the intensity of the second episode at time (t−60). But the combined intensity is the product of I1(t) and I2(t−60). But if I1(t) is zero for t > 60, then the combined intensity would be zero for t > 60.Wait, that can't be right because the problem is asking for the maximum combined intensity over t from 60 to 120, implying that it's non-zero. Maybe I misunderstood the setup.Wait, perhaps the first episode is still playing during the second episode? But no, they are watched back-to-back, so the first episode is from 0 to 60, and the second is from 60 to 120. So, at any time t between 60 and 120, the first episode has already ended, so I1(t) is zero, and I2(t−60) is the intensity of the second episode at time (t−60). Therefore, the combined intensity is I1(t) * I2(t−60) = 0 * I2(t−60) = 0.But that would mean the combined intensity is zero throughout t=60 to t=120, which seems odd because the problem is asking for the maximum, so maybe I'm misinterpreting.Wait, perhaps the combined intensity is the product of the two episodes' intensities at the same time t. But since the first episode ends at t=60, for t > 60, the first episode's intensity is zero, so the product is zero.Alternatively, maybe the combined intensity is the product of the two episodes' intensities at overlapping times. But since they are watched back-to-back, there is no overlapping time. So, perhaps the combined intensity is only non-zero at t=60, where both episodes are transitioning.Wait, at t=60, the first episode ends, and the second episode starts. So, at t=60, I1(60) is the intensity of the first episode at its end, and I2(0) is the intensity of the second episode at its start. So, the combined intensity at t=60 is I1(60) * I2(0). Maybe that's the maximum.But the problem says "over the interval from t = 60 to t = 120," so t=60 is included. So, perhaps the maximum occurs at t=60.Alternatively, maybe the combined intensity is defined as I1(t) * I2(t−60) for t between 60 and 120, meaning that for each t, we take the intensity of the first episode at time t and the intensity of the second episode at time (t−60). But since the first episode only lasts until t=60, for t > 60, I1(t) is zero, so the product is zero. Therefore, the only non-zero point is at t=60, where I1(60) * I2(0).Wait, but let's think about it again. If the second episode starts at t=60, then for t between 60 and 120, the second episode's intensity is I2(t−60). The first episode's intensity is I1(t), but since the first episode ended at t=60, I1(t) is zero for t > 60.Therefore, the combined intensity is zero for t > 60, and only at t=60, it's I1(60) * I2(0). So, the maximum combined intensity is just that value at t=60.Alternatively, maybe the combined intensity is I1(t) * I2(t) for t between 0 and 60, but that's not what the problem says. It says when watched consecutively, the combined intensity is the product of their individual intensity scores at any time t. So, for t between 60 and 120, the first episode is over, so I1(t) is zero, and I2(t−60) is the intensity of the second episode. So, the product is zero.Wait, maybe the combined intensity is defined as I1(t) * I2(t) for t between 0 and 60, and I2(t) for t between 60 and 120. But the problem says "the product of their individual intensity scores at any time t." So, for t between 60 and 120, the first episode is not playing, so I1(t) is zero, so the product is zero.Therefore, the maximum combined intensity would be at t=60, where both episodes are technically "active" in the sense that the first is ending and the second is starting.So, let's compute I1(60) and I2(0).I1(t) = 5t² - 2t + 3.I1(60) = 5*(60)^2 - 2*(60) + 3 = 5*3600 - 120 + 3 = 18000 - 120 + 3 = 17883.I2(t−60) is the intensity of the second episode at time (t−60). So, at t=60, t−60=0, so I2(0) = 5*(0)^2 - 2*(0) + 3 = 0 - 0 + 3 = 3.Therefore, the combined intensity at t=60 is 17883 * 3 = 53649.But wait, is this the maximum? Since for t > 60, the combined intensity is zero, so yes, the maximum is at t=60.Alternatively, maybe the combined intensity is defined differently. Maybe it's the product of the intensities of both episodes at the same time t, but since they are back-to-back, the first episode is only active from 0 to 60, and the second from 60 to 120. So, for t between 0 and 60, the combined intensity is I1(t) * I2(t), but that's not what the problem says. The problem says when watched consecutively, the combined intensity is the product of their individual intensity scores at any time t. So, for t between 60 and 120, I1(t) is zero, so the product is zero.Wait, maybe I'm overcomplicating. Let me read the problem again:"the total combined emotional intensity score is given by the product of their individual intensity scores at any time t. Given that the second episode starts immediately after the first one ends, find the maximum combined intensity score I1(t) ⋅ I2(t−60) over the interval from t = 60 to t = 120."So, it's specifically I1(t) * I2(t−60) for t from 60 to 120.So, for t in [60, 120], I1(t) is the intensity of the first episode at time t, but the first episode only lasts until t=60, so for t > 60, I1(t) is zero. Therefore, I1(t) * I2(t−60) is zero for t > 60.But at t=60, I1(60) is the intensity of the first episode at its end, and I2(0) is the intensity of the second episode at its start. So, the product is I1(60) * I2(0) = 17883 * 3 = 53649.Therefore, the maximum combined intensity is 53649 at t=60.But wait, maybe the problem is considering that the first episode's intensity is still active during the second episode? That doesn't make sense because they are back-to-back. So, the first episode is over at t=60, so its intensity is zero beyond that.Alternatively, perhaps the combined intensity is defined as the product of the intensities of the two episodes at the same time t, but since they are back-to-back, the first episode is only present from 0 to 60, and the second from 60 to 120. So, for t between 0 and 60, the combined intensity is I1(t) * I2(t), but that's not what the problem says. The problem specifies the interval from t=60 to t=120, so we're only considering the time when the second episode is playing, but the first episode has already ended.Therefore, the combined intensity is zero for t > 60, except at t=60, where it's I1(60) * I2(0) = 53649.So, the maximum combined intensity is 53649.Wait, but let me think again. Maybe the problem is considering that the combined intensity is the product of the two episodes' intensities at the same time t, but since they are back-to-back, for t between 60 and 120, the first episode's intensity is zero, so the product is zero. Therefore, the maximum occurs at t=60, which is 53649.Alternatively, maybe the combined intensity is defined as I1(t) * I2(t−60) for t between 60 and 120, meaning that for each t, we take the intensity of the first episode at time t and the intensity of the second episode at time (t−60). But since the first episode only lasts until t=60, for t > 60, I1(t) is zero, so the product is zero. Therefore, the maximum is at t=60.Alternatively, maybe the problem is considering that the combined intensity is the product of the two episodes' intensities at the same time t, but since they are back-to-back, the first episode is only present from 0 to 60, and the second from 60 to 120. So, for t between 0 and 60, the combined intensity is I1(t) * I2(t), but that's not what the problem says. The problem specifies the interval from t=60 to t=120, so we're only considering the time when the second episode is playing, but the first episode has already ended.Therefore, the combined intensity is zero for t > 60, except at t=60, where it's I1(60) * I2(0) = 53649.So, the maximum combined intensity is 53649.Wait, but let me compute I1(60) and I2(0) again to be sure.I1(t) = 5t² - 2t + 3.I1(60) = 5*(60)^2 - 2*(60) + 3 = 5*3600 = 18000; 18000 - 120 = 17880; 17880 + 3 = 17883.I2(t−60) = 5*(t−60)^2 - 2*(t−60) + 3.At t=60, t−60=0, so I2(0) = 5*0 - 2*0 + 3 = 3.Therefore, the product is 17883 * 3 = 53649.Yes, that's correct.Alternatively, maybe the problem is considering that the combined intensity is the product of the two episodes' intensities at the same time t, but since they are back-to-back, the first episode is only present from 0 to 60, and the second from 60 to 120. So, for t between 0 and 60, the combined intensity is I1(t) * I2(t), but that's not what the problem says. The problem specifies the interval from t=60 to t=120, so we're only considering the time when the second episode is playing, but the first episode has already ended.Therefore, the combined intensity is zero for t > 60, except at t=60, where it's I1(60) * I2(0) = 53649.So, the maximum combined intensity is 53649.But wait, let me think if there's another interpretation. Maybe the combined intensity is the product of the two episodes' intensities at the same time t, but since they are back-to-back, the first episode is only present from 0 to 60, and the second from 60 to 120. So, for t between 0 and 60, the combined intensity is I1(t) * I2(t), but that's not what the problem says. The problem specifies the interval from t=60 to t=120, so we're only considering the time when the second episode is playing, but the first episode has already ended.Therefore, the combined intensity is zero for t > 60, except at t=60, where it's I1(60) * I2(0) = 53649.So, the maximum combined intensity is 53649.Alternatively, maybe the problem is considering that the combined intensity is the product of the two episodes' intensities at the same time t, but since they are back-to-back, the first episode is only present from 0 to 60, and the second from 60 to 120. So, for t between 0 and 60, the combined intensity is I1(t) * I2(t), but that's not what the problem says. The problem specifies the interval from t=60 to t=120, so we're only considering the time when the second episode is playing, but the first episode has already ended.Therefore, the combined intensity is zero for t > 60, except at t=60, where it's I1(60) * I2(0) = 53649.So, the maximum combined intensity is 53649.Wait, but maybe the problem is considering that the combined intensity is the product of the two episodes' intensities at the same time t, but since they are back-to-back, the first episode is only present from 0 to 60, and the second from 60 to 120. So, for t between 0 and 60, the combined intensity is I1(t) * I2(t), but that's not what the problem says. The problem specifies the interval from t=60 to t=120, so we're only considering the time when the second episode is playing, but the first episode has already ended.Therefore, the combined intensity is zero for t > 60, except at t=60, where it's I1(60) * I2(0) = 53649.So, the maximum combined intensity is 53649.Alternatively, maybe the problem is considering that the combined intensity is the product of the two episodes' intensities at the same time t, but since they are back-to-back, the first episode is only present from 0 to 60, and the second from 60 to 120. So, for t between 0 and 60, the combined intensity is I1(t) * I2(t), but that's not what the problem says. The problem specifies the interval from t=60 to t=120, so we're only considering the time when the second episode is playing, but the first episode has already ended.Therefore, the combined intensity is zero for t > 60, except at t=60, where it's I1(60) * I2(0) = 53649.So, the maximum combined intensity is 53649.Wait, I think I'm repeating myself, but I just want to make sure I'm not missing something. The key point is that for t between 60 and 120, the first episode's intensity is zero, so the product is zero. The only non-zero point is at t=60, where both episodes are technically at their respective starts/ends.Therefore, the maximum combined intensity is 53649.So, to summarize:1. The total emotional impact is the integral of I(t) from 0 to 60, which is 356,580.2. The maximum combined intensity when watching two episodes back-to-back is 53,649 at t=60.I think that's it.</think>