Three equations, three variables

[Mustcrackgmat]

Is wxy equal to -1?

(1) w, x, and y are all negative.

(2) w + x + y = -3
I understand that to answer a question for three variables, one must have three equations. But if I combine statement 1 and 2, my only answer is w=x=y=-1 . No variable can have zero value as statement one says all three variables are negative. I thought the answer was C. Its E though. Please help

[dominhtri1995]

Hi Mustcrackgmat

When you combine (1) and (2):
w,x and y are not necessary integers
Hence we can not jump to the conclusion that w=x=y=-1
=> (E)


Regard,

[Brent@GMATPrepNow]

Is wxy equal to -1?

(1) w, x, and y are all negative.
(2) w + x + y = -3

dominhtri1995's explanation is great. I just thought I'd throw in a second set of values to show why the combined statements are NOT SUFFICIENT.

Target question: Is wxy equal to -1?

Statements 1 and 2 combined
Consider these two conflicting cases:
Case a: w = -1, x = -1, y = -1, wxy EQUALS -1
Case b: w = -1/2, x = -1/2, y = -2, wxy DOES NOT equal -1
Since we cannot answer the target question with certainty, the combined statements are NOT SUFFICIENT

Answer = E

Cheers,
Brent