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Is k positive?

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Source: — Data Sufficiency |

Re: Is k positive?

by Brent@GMATPrepNow » Thu Jul 16, 2020 5:39 am
BTGModeratorVI wrote:
Mon Jul 13, 2020 7:53 am
Is k positive?

(1) k + 1 < 1 − k
(2) 1/k < 0

Answer: D
Source: Economis GMAT
Target question: Is k positive?

Statement 1: k + 1 < 1 − k
Add k to both sides of the inequality to get: 2k + 1 < 1
Subtract 1 from both sides of the inequality to get: 2k < 0
Divide both sides by 2 to get: k < 0 (in other words, k is negative)
The answer to the target question is NO, k is definitely not positive
Since we can answer the target question with certainty, statement 1 is SUFFICIENT

Statement 2: 1/k < 0
Since 1 is POSITIVE, this statement is telling us that: POSITIVE/k = NEGATIVE
This means k must be negative.
The answer to the target question is NO, k is definitely not positive
Since we can answer the target question with certainty, statement 2 is SUFFICIENT

Answer: D

Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
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