Scott Woodbury-Stewart

GMAT OFFICIAL GUIDE DS – If a and b are positive integers, is a/b…

If a and b are positive integers, is a/b…

Solution:

We are given that a and b are positive integers and we must determine:

Is a/b < 9/11?

or

Is a/b <0.818181…?

Statement One Alone: 

a/b < 0.818

Using the information in statement one we know that a/b < 0.818, so a/b < .818181… and we can answer YES to the question. Statement one alone is sufficient to answer the question. We can eliminate answer choices B, C, and E.

Statement Two Alone: 

b/a > 1.223

To better analyze statement two, we can rephrase the question by reciprocating both sides of the inequality (but remember to flip the inequality sign):

Is a/b < 9/11?

to

Is b/a > 11/9?

i.e.,

Is b/a > 1.222…?

Using the information in statement two, we know that b/a > 1.223, so b/a > 1.222… and we can again answer YES to the question. Statement two alone is sufficient to answer the question.

Answer: D 

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