Data Sufficiency

why not A? Please explain

IMO E.

Question is bassically asking that what is the value of
z and n.

From 2nd we get that,

Z>0 so it could be a fraction or could be digit.
so satisfy this statement n has to be 0 to make this equal to 1.
i.e 1/2^0=1.
Insufficient.


From 1st we get that N is not equal to 0.
completely opposite of what we need.
Insufficient.

I hate the GMAT.

A is not sufficient because Z can be -1 or 1. Consider
1) Z=-1. Therefore -1^2 = 1
2) Z= 1. Therefore 1^2 = 1

Because we have more than one value for Z, when n = non zero integer, A is not sufficient.

Combining both statements, I'd say C is the answer because Z has to be 1 when n is a non zero integer to be equal to 1

This freaking exam is not difficult. They just put in so many brain teasers which are not normally tested in high school/college hence the rude shock received when you find out you missed question

Arghhh

Well I agree, I missed the negative 1. thanks, OA is C