GMAT prep question, thanks : )

[alcatraz]

If n and p are integers, is p > 0 ?

1) n+1 > 0
2)np > 0





OA: C

[shubham_k]

n+1 > 0. thus n > -1. so n= {0,1,2,3,4,5.......} ( n is an integer ).
np > 0 thus both n and p have to be greater than zero because the other possibility where n and p both < 0 but earlier condition doesnt allows that. Thus n and p > 0. Conclusion through both the startements hence correct answer C.

[aneesh.kg]

Statement (1) talks about 'n' and not about 'p', so it's useless.

Statement (2) can be true when both n > 0 and p > 0, OR when n < 0 and p < 0. So, 'p' can hold any value and this statement is also useless.

Let's try to combine them.

The first statement says that n > -1 and n is an integer. So, n is an integer >= 0.
When we combine this with the second statement, we see that 'n' can't be 0 because 'np' can't be 0. Now, since n > 0 and np > 0, 'p' has to be > 0.

That answers the question with a YES, and therefore [C] is the answer.