Scott Woodbury-Stewart

GMAT OFFICIAL GUIDE DS – In Mr. Smith’s class, what is the ratio of…

In Mr. Smith’s class, what is the ratio of…

Solution:

We need to determine the ratio of the number of boys to the number of girls. If we denote the number of boys as b and the number of girls as d, we can say:

b/g = ?

Statement One Alone:

There are 3 times as many girls as boys in Mr. Smith’s class.

Using statement two we can say:

g = 3b

g/b = 3

b/g = 1/3

Statement one is sufficient to answer the question. We can eliminate answer choices B, C, and E.

Statement Two Alone:

The number of boys is 1/4 of the total number of boys and girls in Mr. Smith’s class.

Using statement two we can say:

b = ¼(b + g)

4b = b + g

3b = g

b/g = 1/3

Statement two is sufficient to answer the question.

Answer: D