Hi ash4gmat,

This DS question is built around a couple of math concepts; if you recognize those concepts, then you can actually avoid a lot of 'step-heavy' math and still get the correct answer.

We're told that N is an integer. We're asked for the value of N.

1) N(N+1) = 6

Given that N is an integer, "N" and "N+1"are consecutive integers. Can you think of two consecutive integers that have a product of 6?

The obvious answer is 2 and 3, so the answer to the question would be 2.

HOWEVER... can you think of any OTHER consecutive integers that have a product of 6....?

There's also -3 and -2, so the answer to the question would be -3.
Fact 1 is INSUFFICIENT.

2) 2^(2N) = 16

The only "power of 2" that equals 16 is 4, since 2^4 = 16 (but 2^(-4) = 1/16, so there's no 'negative solution'). This means that 2N = 4, so N=2.
Fact 2 is SUFFICIENT

Final Answer: B

GMAT assassins aren't born, they're made,
Rich