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a mistake in the OFFICIAL Test?

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a mistake in the OFFICIAL Test?

by Carloblacksun » Tue Dec 02, 2008 9:00 am
I post a very interesting problem...I cannot explain myself why E is wrong...as you can see the source is the official GMAT practice test...
What do you thing?

to me the first equation becomes X = 1/2 + Y
while the second = simply X > Y

this means that in case Y = 1 and X = 3/2 the assumption is true, but if Y = -1/2 and X = 0 the assumption is false...
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by gmataug08 » Tue Dec 02, 2008 9:16 am
from stmt 2 .... we know that there are only 2 choices,

choice 1 : both X & Y negative
choice 2 : both X & Y positive

and either way , for sure X > Y (mandatory condition).

from stmt 1..... x- y = 1/2
by applying the 2 choices from stmt 1,

when x & y positive , it implies that X has to be greater than Y to get a positive result (that is 1/2) .......which satisfies the inferences we got from stmt 2 too.

when x & y are negative, it implies that x must be less that Y to get a positive result from subration ........which fails the must condition we got from stmt 2.

hence , by combining both stmts we can be sure that X & Y are positive.
ans C .
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by Carloblacksun » Tue Dec 02, 2008 9:24 am
you are right!!

X/Y > 1 does not mean that X > Y simply!!!
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