Word Problems

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Word Problems

by BTGmoderatorRO » Sun Dec 24, 2017 9:07 am
Ken wants to ship abroad 16 cubic meters of fine fabric. Shipping costs $(x+y) per cubic meter for the first N cubic meters, and $(x−y) per cubic meter, for the part of the volume that exceeds N cubic meters. How much will Ken pay for the shipment, in dollars, in terms of N,x and y?


A. 16x+(2N-16)y
B 16x+2(16-N)y
C. (16-N)y+N*x
D. N*x+2(16-N)y
E. 16(x-y)+N*y

OA is A

I need a perfect interpretation of this question! An Expert contribution would be highly appreciated.
Source: — Problem Solving |

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by elias.latour.apex » Sun Dec 24, 2017 10:49 am
The easiest way to solve problems of this type is to pick numbers for N, x, and y. In my case, I will pick N=8, x=8, and y=2. If that is so, then Ken will pay $10/meter for the first 8 meters and $6 per meter for the last 8 meters of fabric. According he will pay $80+48 = 128 total. This is my target. If I substitute N, x, and y into the equations, the right equation will give me my target answer.

A) 16(8)+(0)6 = 128. This is my target answer.
B) 16(8)+2*(8)(2) will be too big.
C) 8(2)+8(8) = 16+64. Too small.
D) 8*8+2(8)(2) = 64+32. Too small.
E) 16(8)+8*2 will be too big.

So (A) must be the answer.

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