hi guys. i saw this question in my last gmat test by powerprep. If xy=1, what is the ans for the following
2(x+y)(x+y) .it was a tough one. thanks.
____________
2(x-y)(x-y)
PS: The ans is 16.
equations
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Hi,emiflo wrote:hi guys. i saw this question in my last gmat test by powerprep. If xy=1, what is the ans for the following
2(x+y)(x+y) .it was a tough one. thanks.
____________
2(x-y)(x-y)
PS: The ans is 16.
that's definitely not an accurate restatement of the question.
Just plug in x=y=1 (satisfying xy=1) and you get:
2(2)(2)/2(0)(0) = 8/0 which is undefined, certainly not 16.
I'm guessing that one of the conditions was that xy did NOT equal 1 and there was other information as well.
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well sir,Stuart Kovinsky wrote:
Just plug in x=y=1 (satisfying xy=1) and you get:
2(2)(2)/2(0)(0) = 8/0 which is undefined, certainly not 16.
I'm guessing that one of the conditions was that xy did NOT equal 1 and there was other information as well.
am i missing something here
the question doesnt say both numbers are integer that means
x=2 and y=1/2 still validates xy=1
and i get 25/9 in that case which gives some value...
so i think outcome now depends upon assumption of number like 3 and 1/3 and so on
question is not 100% correct ...
but am i missing something in what i am doing
thanks
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You could pick values that make sense - but GMAT questions have to be true for all values, not just some of them.frank1 wrote:well sir,Stuart Kovinsky wrote:
Just plug in x=y=1 (satisfying xy=1) and you get:
2(2)(2)/2(0)(0) = 8/0 which is undefined, certainly not 16.
I'm guessing that one of the conditions was that xy did NOT equal 1 and there was other information as well.
am i missing something here
the question doesnt say both numbers are integer that means
x=2 and y=1/2 still validates xy=1
and i get 25/9 in that case which gives some value...
so i think outcome now depends upon assumption of number like 3 and 1/3 and so on
question is not 100% correct ...
but am i missing something in what i am doing
thanks
![Image](https://i.imgur.com/YCxbQ7s.png)
Stuart Kovinsky | Kaplan GMAT Faculty | Toronto
Kaplan Exclusive: The Official Test Day Experience | Ready to Take a Free Practice Test? | Kaplan/Beat the GMAT Member Discount
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