Bunuel wrote:

Is \(x^2y^3w^4z^1 < 0\) ?

(1) yz < 0

(2) z < 0

Hi,

there are two sets of answer-

1) A as the answer --- Not speaking about any of the variables being 0..

2) E as the answer--- Correctly taking 0 as an option for variables ..lets see the equation first and what is required..

\(x^2y^3w^4z^1 < 0\)

1) when all are non-zero integers..\(x^2w^4\) will be > 0, we have to check if y and z are of opposite sign..

2) if any of the integer is 0..if any integer is zero, entire equation will be 0

AND our answer to "Is \(x^2y^3w^4z^1 < 0\) ?" will be NO..

and suff..

lets see the statements-

(1) yz < 0this shows that y and z are of opposite sign, so ans is YES..

But say x is 0, then ans will be NO..

Insuff

HAD the q been \(x^2y^3w^4z^1 > 0\), this statement would have been suff as ans would be NO in both cases, but not NOW

(2) z < 0Clearly insuff

Combined,still insuff as the cases as shown in statement 1 still remain

E

_________________

1) Absolute modulus : http://gmatclub.com/forum/absolute-modulus-a-better-understanding-210849.html#p1622372

2)Combination of similar and dissimilar things : http://gmatclub.com/forum/topic215915.html

3) effects of arithmetic operations : https://gmatclub.com/forum/effects-of-arithmetic-operations-on-fractions-269413.html

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