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Re: Is x^y less than or equal to y^x [#permalink]
22 Sep 2011, 22:01

Are you sure this question is correct?

Y can also be zero if you combine statements 1 & 2. Y= 0 or 2. The form can be 0^0 & this form is undefined. Does the question specify that both x & y are positive/non-zero? _________________

Hit kudos if my post helps you. You may send me a PM if you have any doubts about my solution or GMAT problems in general.

Re: Is x^y less than or equal to y^x [#permalink]
05 Oct 2011, 02:44

Expert's post

braxus wrote:

Could someone please clarify - When the 2 statements are taken together - i.e x=y^2 and x=2y, we get y^2 = 2y y^2 - 2y=0 y(y-2)=0

Therefore y=0 or y=2 Clearly it creates 2 different answers for the the inequality. I believe (E) should be the answer

On solving this, you do get two different values for y. But variables cannot take values which make an expression undefined e.g. given y/x, x cannot be 0 since division by 0 is not allowed. Given x^y, both x and y cannot be 0 since 0^0 is not defined. Hence y will not take the value 0. y must be 2 only. _________________