prime factors

ketkoag wrote:If N's prime factors are 2 and 3, N=?
1) N<9
2) N has 12 factors.

If they talk about prime factors of N, shall we take N as a positive integer? If yes, then (1) alone is sufficient to answer the stem.

For (2) with the same intention (N as a positive integer), following are the ways in which N could have 12 factors:

N = (2^1)*(3^5), N = (2^2)*(3^3), N = (2^3)*(3^2), N = (2^5)*(3^1), hence it is alone not sufficient.

Go for A.

sanju09, i have a question for u. if the question has mentioned that 'If N's prime factors are 2 and 3', then would it mean that there are no factors other than 2 and 3? coz i feel that its true always.
please lemme know if i'm wrong.....

ketkoag wrote:If N's prime factors are 2 and 3, N=?
1) N<9
2) N has 12 factors.

This is clearly NOT a valid GMAT question - what's the source? I wouldn't trust it in the future.

On the GMAT, the two statements will NEVER contradict each other. In other words, there has to be at least some overlap between the two.

There is no number less than 9 that has 12 factors, so this question is impossible.

(We generally don't speak about prime factors of negative numbers, at least on the GMAT.)

ketkoag wrote:sanju09, i have a question for u. if the question has mentioned that 'If N's prime factors are 2 and 3', then would it mean that there are no factors other than 2 and 3? coz i feel that its true always.
please lemme know if i'm wrong.....

First of all this was not a problem that I should have attempted from the GMAT point of view, I must thank Stuart for pointing that out. I somehow took and treated each statement deadly alone and independent from each other, but I never minded that these are contradicting each other.

Yes ketkoag! Given that, my answer is still A. George has children named , Neil, Betty, and Gerard. It logically implies that George has only three children. Moreover, Neil and Gerard are George's children, never implies that George has exactly two children.