Is k > 0?

Assuming you Q is this:

If -10<k<10>0?

It says K lies between -10 and 10 then looking at the statements

1. 1/K >0 there is only 1 value of K that makes 1/k >than 0 that is K= 1 and as per the condition k >0.

2. k^2>0

Plug in values

K^2 K Is K>0
4 2 Yes
4 -2 no

So we have a yes and no answer therefore it is not sufficient.

Then ans is A

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Thanks for the solution. The original question was - -10 < k < 10, is k > 0?

Mostly in DS questions, we get something like, what is the value of x, given that x^2 > 4.

We cant find a solution to it because we assume, x > +2 or -2. I was thinking on the same terms for the equation k^2 > 0, and saying that k > +0 or -0 would be wrong.

I don't agree with "saege's" explaination for A.

i) When we have 1/k>0 it simply says that 1/k is positive. 1/k can also be a fraction example 1/2 for k=2 and it can be another whole number example 2 for k=0.5. But as we have 1/k positive, we know k is also positive. Sufficient.

ii) This says k^2>0 which means square of k is positive. But k could be both positive or negative. Insufficient.

Thus answer is A.

Follow this positive negative approach to save time as you wouldn't need to consider all possible cases.