princessss wrote:If k is not equal to 0, 1, or -1, is 1/k>0?

(1) 1/(k-1)>0

(2) 1/(k+1)>0


My question is why B isn't correct.
If k is not 0,1 or -1 it can be 2,3 ... and it can be -2,-3 etc.
If we say that k is 2 than 1/(2+1) > 0 true
But, since it can't be -1 if k is negative the fraction can be >0. Doesn't that make B sufficient? K must be positive?
The correct answer is A.
Please help

GMATGuruNY wrote:
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.

goyalsau wrote:

GMATGuruNY wrote:
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.

How can you rewrite statements like this,
As per i know we can't do anything with inequalities unless we don't know whether they are positive or negative........