Data Sufficiency

sparkle6 wrote:If Z^n = 1, what is the value of z?
1) n is a nonzero integer
2) z > 0

[spoiler]OA: C, but how is 1 sufficient? Can't Z be -1 if n is an even power?[/spoiler]

Before we examine the two statements, let's take some time to draw some conclusions about z and n if we are told that z^n = 1.

If z^n = 1, there are 3 possible cases:
case a: z=any number and n=0
case b: z=1 and n=any number
case c: z=-1 and n=any even integer

Statement 1: n is a nonzero integer
This rules out case a, which leaves us with cases b (z=1) and c (z=-1)
As such, statement 1 is not sufficient

Statement 2: z > 0
This rules out case c, which leaves us with cases a (z=any positive number) and b (z=1)
As such, statement 2 is not sufficient

Statements 1 & 2:
When we combine the statements, we can rule out cases a and c, leaving us with only case b (z=1)
As such, the statements combined are sufficient and the answer is C

Cheers,
Brent