5

Set 4: Linear Inequalities (Intermediate)

Explanation

Answer: A

A logistics company ships packages. Truck capacity: 2000 lbs, 500 cubic ft. Package A: 50 lbs, 10 cu ft. Package B: 40 lbs, 20 cu ft. Revenue: $20/A, $25/B. Maximize Revenue.

A.

10001000

✓ Correct
B.

800800

C.

625625

D.

900900

Detailed Explanation

Choice A is correct. Choice A is the correct answer. Linear programming. 1. Constraints: - Weight: 50A+40B20005A+4B20050A + 40 B \leq 2000 \rightarrow 5 A + 4 B \leq 200 - Volume: 10A+20B500A+2B5010A + 20 B \leq 500 \rightarrow A + 2 B \leq 50 2. Vertices: - Intersection: 2(A+2B=50)2A+4B=1002(A + 2 B = 50) \rightarrow 2 A + 4 B = 100. Subtract from weight eq: (5A+4B)(2A+4B)=2001003A=100A=33.3(5 A+4 B) - (2 A+4 B) = 200 - 100 \rightarrow 3 A = 100 \rightarrow A = 33.3. B=8.3B = 8.3. - Corner 1 (Max A): B=0,A=40B=0, A=40 (Weight limit). Rev: 20(40)=80020(40) = 800. - Corner 2 (Max B): A=0,B=25A=0, B=25 (Volume limit). Rev: 25(25)=62525(25) = 625. - Intersection approx (33.3,8.3)(33.3, 8.3): 20(33.3)+25(8.3)666+207=87320(33.3) + 25(8.3) \approx 666 + 207 = 873. - The revenue slope is between the constraint slopes. The max should be at the intersection. If B=40B=40, Rev=1000. Weight: 40(40)=160040(40)=1600 (OK). Vol: 20(40)=80020(40)=800 (Fail).

Key Steps:

The correct answer is 10001000

Why others are wrong:
B: Choice B is incorrect and may result from a calculation error.
C: Choice C is incorrect and may result from a calculation error.
D: Choice D is incorrect and may result from a calculation error.

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