Is 1/(a-b) < b-a?
(1) a < b
(2) 1 < la-bl (modulus a-b)
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ganeshrkamath
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Statement 1: a < bvinay1983 wrote:Is 1/(a-b) < b-a?
(1) a < b
(2) 1 < la-bl (modulus a-b)
(a-b) < 0 and (b-a) > 0
The question becomes
1/negative < positive?
Sufficient.
Statement 2:
Two cases:
Case 1: (a-b) > 1
Case 2: (a-b) < -1
We get a NO for Case 1 and a YES for Case 2.
Not sufficient.
Choose A
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Kelley School of Business (Class of 2016)
GMAT Score: 750 V40 Q51 AWA 5 IR 8
https://www.beatthegmat.com/first-attemp ... tml#688494
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Brent@GMATPrepNow
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Note: My solution is very similar to ganeshrkamath's, but mine uses specific values for a and b in statement 2.vinay1983 wrote:Is 1/(a-b) < b-a?
(1) a < b
(2) 1 < |a-b|
Target question: 1/(a-b) < b-a?
Statement 1: a < b
From this, we can conclude that a-b is negative, and a+b is positive
So, the question becomes: Is 1/negative < positive?, and the answer is a resounding YES!
Since we can answer the target question with certainty, statement 1 is SUFFICIENT
Statement 2: 1 < |a-b|
There are several values of a and b that satisfy this condition. Here are two:
Case a: a = -2 and b = 0, in which case 1/(a-b) < b-a
Case b: a = 2 and b = 0, in which case 1/(a-b) > b-a
Since we cannot answer the target question with certainty, statement 2 is NOT SUFFICIENT
Answer = A
Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
