Hi All,

It looks like everyone who's responded so far is comfortable using Number Properties to get to the correct answer. Any question that can be solved with Number Properties can also be solved by TESTing VALUES.

We're asked if |X^7|(Y^3)(Z^4) > 0. This is a YES/NO question.

Fact 1: XY < 0

This tells us that we have 1 POSITIVE and 1 NEGATIVE variable

IF....

X = 1

Y = -1

Z = 1

|1^7|[(-1)^3](1^4) = (1)(-1)(1) = -1 and the answer to the question is NO.

IF....

X = -1

Y = 1

Z = 1

|(-1)^7](1^3)(1^4) = (1)(1)(1) = 1 and the answer to the question is YES.

Fact 1 is INSUFFICIENT

Fact 2: YZ > 0

This tells us that either BOTH are positive OR BOTH are negative

IF....

X = -1

Y = 1

Z = 1

(from above), the answer to the question is YES.

IF...

X = 1

Y = -1

Z = -1

|1^7|[(-1)^3][(-1)^4] = (1)(-1)(1) = -1 and the answer to the question is NO.

Fact 2 is INSUFFICIENT

Combined, we know...

XY < 0

YZ > 0

We can use our prior work (from Fact 2) to quickly deal with this last step:

IF....

X = -1

Y = 1

Z = 1

(from above), the answer to the question is YES.

IF...

X = 1

Y = -1

Z = -1

(from above) and the answer to the question is NO.

Combined, INSUFFICIENT

Final Answer:

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

Rich

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