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Is x^y less than or equal to y^x? 1) rootx=y 2) x=2y [#permalink]
 22 Sep 2011, 07:39
Question Stats:
64% (02:32) correct
35% (01:21) wrong based on 1 sessions
Is x^y less than or equal to y^x? 1) rootx=y 2) x=2y
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Re: Is x^y less than or equal to y^x [#permalink]
22 Sep 2011, 08:04
C.
1. X= y^2 (doesn't Hek=lp)
2. X=2y (Doesn't help by itself)
but when we use both.. 2y=Y^2 thus Y=2... now we can solve!
So C!
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Re: Is x^y less than or equal to y^x [#permalink]
22 Sep 2011, 23:01
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?
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Re: Is x^y less than or equal to y^x [#permalink]
23 Sep 2011, 03:43
I also got two different set of values.
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Re: Is x^y less than or equal to y^x [#permalink]
29 Sep 2011, 07:29
zura wrote: Is x^y less than or equal to y^x?
1) rootx=y
2) x=2y A tough question. Took 3 mins to solve  1. x = y^2 Means and y are +ve Case 1: x = 0.01, y =0.1 with these values x^y > y^x Case 2 : x = y =1 with these values x^y = y^x Case 3: x = 4, y =2 with these values x^y = y^x Case 4: x = 9, y =3 with these values x^y < y^x So Insufficient 2) x = 2y Insufficient 3) Combininng we get only one option x = 4, y =2, in which x^y = y^x Sufficient, hence (C)
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Re: Is x^y less than or equal to y^x [#permalink]
29 Sep 2011, 08:02
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
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Re: Is x^y less than or equal to y^x [#permalink]
29 Sep 2011, 09:51
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 For y=0, x=0 0^0 = 0^0 For y=2, x = 4 2^4 = 16 = 4^2 Hence (C)
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Re: Is x^y less than or equal to y^x [#permalink]
03 Oct 2011, 02:23
Admin, please, ban this man!
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If my post is useful for you not be ashamed to KUDO me!
Let kudo each other!
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Re: Is x^y less than or equal to y^x [#permalink]
05 Oct 2011, 03:44
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.
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Re: Is x^y less than or equal to y^x
[#permalink]
05 Oct 2011, 03:44
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