Mcgraw hills gmat 2008 practice test

Here are a couple ways to solve this one.

First algebraically:

P people were asked 2 questions. 2/5 answered yes to the first question.

So, P(2/5) answered Yes.

Of these people that answered yes to the first question, 1/3 answered yes to the second question.

So (2p/5) * (1/3) = 2P/15

So 2P/15 are the people who answered Yes to both questions. We want to know how many people didn't answer yes to both questions so P - 2P/15 = 13P/15

E.


Now solving this picking a smart number.

15 is the smart number since the denominators are 3 and 5 that we are working with.

So we will say 15 people were asked the 2 questions.

15 * 2/5 = 6 answered yes to the first

6 * 1/3 = 2 answered yes to both

15 - 2 = 13 didn't answer yes to both.

Fill in 15 for P in the answer choice and see which one results in 13. E is the only one.