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algebra

by heymayank08 » Mon Apr 30, 2012 8:46 pm
Q) If x and y are positive, is x3 > y?
(1) √x > y
(2) x > y


[spoiler]IMO: A
since if both are +ve then
x>y^2
if this is so then x^3>y
what is the fault in this approach???
OA: E[/spoiler]
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by shantanu86 » Mon Apr 30, 2012 9:37 pm
IMO [spoiler][E][/spoiler]

This question is an easy one if you know the concept that for two positive numbers x and y

if x>y

then x^n may not be > y.. this is true if x& y are less than 1 because if a number is <1 then taking its power >1 will always decrease it.

eg.

.5 > .4
but
.5^2 = .25 <.4

Thus, the answer is [spoiler][E][/spoiler].
If you feel like it, hit thanks :)
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by heymayank08 » Mon Apr 30, 2012 10:31 pm
thnx a ton
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