In order for 1/k to be positive, k must be positive. Rewritten, the question is asking:
Is k>0?
Statement 1:
In order for 1/(k-1) to be positive, k-1 must be positive. Rewritten, statement 1 tells us:
k-1>0
k>1
Thus, k>0. Sufficient.
Statement 2:
In order for 1/(k+1) to be positive, k+1 must be positive. Rewritten, statement 2 tells us:
k+1>0
k>-1
Thus, k could be negative (k= -1/2, for example), or k could be positive (k=1, for example). Insufficient.
The correct answer is A.
Another GMATprep question
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Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.
As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.
For more information, please email me (Mitch Hunt) at [email protected].
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