wait what?

something is seriously wrong here, as elementary number picking is quick to show.

first off, the 2's clearly cancel, so get rid of them.

if we let x = 2 and y = 1/2, then the expression is (5/2)^2 / (3/2)^2, which is 25/9 = 2.77777..., an answer that is clearly not listed. worse yet, plugging in other numbers leads to other answer choices.

incidentally, the only numbers that satisfy the initial constraint (xy = 1) and actually give the answer 16 are plus or minus (√15)/5 and (√15)/3 - two numbers that, i can confidently say, no one is going to pick anytime soon.

wait, uh, well, i made up a problem that looks at least somewhat like this one, with the desired solution.

here you go:

simplyjat wrote:This question is a mistake in GMATPrep, The original intent of the question is to ask

If XY = 1
Than what is the value of (2^[(x+y)^2])/(2^[(x-y)^2]) ?
Which simplifies to
(2^(x^2))*(2^(y^2))*(2^(2xy)) / (2^(x^2))*(2^(y^2))*(2^(-2xy))
=> (2^(2xy)) / (2^(-2xy))
=> (2^(4xy))
=> (2^(4*1))
=> 2^4
=> 16

that's awesome

where'd you get the fix? did you figure it out yourself?