Copper pipe costs x cents per foot in 8-foot lengths, and x + y cents

Question

Copper pipe costs x cents per foot in 8-foot lengths, and x + y cents per foot in shorter lengths. What is the lowest possible price, in cents, of 51 feet of pipe in terms of x and y?

A. 51(x + y)
B. 51x
C. 48x + 3y
D. 48(x + y)
E. 51x + 3y

LevanKhukhunashvili · Answer

51=8*6+3

So we need 6 bars of 8-foot length, which costs 48x
and 3 foot shorter bar, which costs 3(x+y) 
48x+3(x+y)=51x+3y

IMO
Ans:  E

KarishmaB · Answer

Since the cost of per foot is lower in 8-foot lengths, we should try to get as many 8-foot lengths as possible.

So we get 6 of the 8-foot lengths for a total of 48 feet of copper pipes. Rest of the 3 feet will cost x+y cents per foot.
So total cost = 48x + 3(x+y) = 51x + 3y

Answer (E)

Archit3110 · Answer

total required length = 51
so 
48x+3x+3y; 51x+3y
IMO E

ScottTargetTestPrep · Answer

Solution:
 
For 51 feet of pipe, the cheapest option is to buy six 8-foot pipes and one 3-foot pipe. Therefore, the lowest possible price, in cents, of 51 feet of pipe, is:

6 * 8 * x + 1 * 3 * (x + y) = 48x + 3x + 3y = 51x + 3y

Answer: E

Copper pipe costs x cents per foot in 8-foot lengths, and x + y cents

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GMAT Problem Solving (PS) Questions

Copper pipe costs x cents per foot in 8-foot lengths, and x + y cents

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