Jeff Miller

GMAT OFFICIAL GUIDE PS – A case contains c cartons…

A case contains c cartons…

Solution:

We are given that a case contains c cartons. Each carton contains b boxes, and each box contains 100 paper clips. Thus we can say the following:

c x b x 100 = 100bc paper clips per case. Thus, 2 cases would contain 2 x 100bc = 200bc paper clips.

Answer: C

Note: Normally, we try not to plug in numbers when dealing with variable questions. However, if we truly could not grasp how to solve this with variables we could use convenient numbers for b and c. Let’s say b = 2 and c = 3. The new question is now:

A case contains 3 cartons. Each carton contains 2 boxes, and each box contains 100 paper clips. How many paper clips are contained in 2 cases?

Thus we can say:

3 x 2 x 100 = 600 paper clips per case. Thus there are 2 x 600 = 1,200 paper clips in 2 cases. Let’s now plug our values for b and c into the answer choices to see which answer choice gives us 1,200.

(A) 100bc

100 x 2 x 3 = 600

Answer choice A is not correct.

(B) 100b/c

(100 x 2)/3 = 200/3

Answer choice B is not correct.

(C) 200bc

200 x 2 x 3 = 1,200

Answer choice C is correct.

(D) 200b/c

(200 x 2)/3 = 400/3

Answer choice D is not correct.

(E) 200/bc

200/(2 x 3) = 200/6

Answer choice E is not correct.