Is 1/(a - b) < b – a ? (1) a > b (2) (a + b)(a –

[hazelnut01]

Is 1/(a - b) < b - a ?

(1) a > b
(2) (a + b)(a - b) > 0

OA=A

[Jay@ManhattanReview]

Is 1/(a - b) < b - a ?

(1) a > b
(2) (a + b)(a - b) > 0

OA=A

Hi ziyuenlau,

Question: Is 1/(a - b) < b - a?

Looking at (a - b) and (b - a), one can intuit that one of them would be a positive number and the other would be a negative number; so the fate of the question depends on the signs a and b take.

Statement 1: a > b

=> (a - b) is positive and (b - a) is negative

Thus, 1/(a - b) is positive.

Or, 1/(a - b) > b - a. The answer is NO. Sufficient.

Statement 2: (a + b)(a - b) > 0

=> a^2 > b^2

=> |a| > |b|

If a and b both are positive, a > b, The answer is NO.

However, if a and b both are negative, a < b, The answer is Yes. Insufficient.

The correct answer: A

Hope this helps!

Relevant book: Manhattan Review GMAT Data Sufficiency Guide

-Jay
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