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| Fraction problem |
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Sudhan
Guest
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Y=(X^2-Y^2)/X-Y
= (X-Y) (X+Y)/X-Y = X+Y Y=X+Y WHICH MEANS X=0 We can rephrase the question as Is X=0? AD BCE Grid A) Talk about Y which is not needed INSUFF B) Talk about Y which is not needed INSUFF Combining A & B we get x+y=3 x-y=2 Solving for X we get x=5/2 From this we can say C is sufficient to answer the question. Hope it helps. |
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Ron Purewal
MGMAT STAFF
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you need to post a source for this problem. please do so in the next couple of days, or else we'll have to delete the thread.
thank you. |
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| Fractions-Princeton Review |
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gmatstudent
Guest
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Ron, the source of the problem is above.
Thank you |
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| Re: *Fraction problem |
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Ron Purewal
MGMAT STAFF
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are you sure you've posted this question correctly? as another poster said, you can rephrase the original statement to y = x + y, which means that x = 0. so, we have: 'if x = 0, then what is the value of y?' technically, either (1) or (2) is sufficient, because (1) says 0 + y = 3, and (2) says 0 - y = 2. but that's where we run into problems: we have 2 statements that contradict each other, a situation that's strictly not allowed on the real test. worse yet, if you take the two statements together, you can solve them as simultaneous equations, yielding x = 2.5 and y = 0.5. but then (x^2-y^2)/(x-y) is 6/2 = 3, which definitely doesn't equal y. something is wrong in problemville. but wait - you didn't include parentheses around x-y in the original. are you saying it's actually the fraction (x^2 - y^2) divided by JUST x, and then that fraction minus y? because that would be a whole different ballgame. if so, just post to that effect. |
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| Fraction problem |
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