D
In both stmts remember this Positive / Positive > 0.
Stmt 1 states that k-1 > 0. We know that K > 1. Sufficient
Similarly, we get k+1>0. Since question states k is not equal to 0, -1, 1, K must be > 1.
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If k not = 0, 1, -1, is 1/k >0?
Source: Beat The GMAT — Data Sufficiency |
If k is an integer, I agree with crackgmat07, but because the original question leaves out that statement, the answer should be A.
(2) only says the k+1>0, but k can be in the range -1<k<0 if it isn't an integer, hence k could be k<0, so (2) would be insufficient
(2) only says the k+1>0, but k can be in the range -1<k<0 if it isn't an integer, hence k could be k<0, so (2) would be insufficient
andy123: could you please explain how are you translating 1/(k+1) > 0 to k+1 > 0 ?
For (Num/Den) > 0, Either (Num > 0 and Den > 0) or (Num < 0 and Den < 0). In this case, Num = 1 is > 0 so, Den = (k+1) > 0.
For (Num/Den) > 0, Either (Num > 0 and Den > 0) or (Num < 0 and Den < 0). In this case, Num = 1 is > 0 so, Den = (k+1) > 0.
Thanks,
Nand
Nand
Answer has to be A
Question asks : is 1/K>0
1>0
hence 1/K will be greater than 0 only if K>0
Statement1
----------
1/K-1 > 0
==> K-1>0
==> K>1
All numbers >1 will be +ve hence 1/K >0 ,sufficient
Statement2
----------
1/k+1 > 0
==>k+1>0
==>k>-1
if k=-0.9,1/k<0
if k=2,1/k>0
No fixed sign,hence insufficient.
Question asks : is 1/K>0
1>0
hence 1/K will be greater than 0 only if K>0
Statement1
----------
1/K-1 > 0
==> K-1>0
==> K>1
All numbers >1 will be +ve hence 1/K >0 ,sufficient
Statement2
----------
1/k+1 > 0
==>k+1>0
==>k>-1
if k=-0.9,1/k<0
if k=2,1/k>0
No fixed sign,hence insufficient.
