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Exponent algebra

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Exponent algebra

by ash_maverick » Wed Feb 28, 2007 8:23 pm
x and y are positive integers.if [5^x]-[5^y]=[2^(y-1)][5^x] , what is the value of xy?

(A) 48
(B) 36
(C) 24
(D) 18
(E) 12--ans

Please explain
corrected...sorry for the misstake.

please provide the explanation...
Last edited by ash_maverick on Thu Mar 01, 2007 11:32 am, edited 2 times in total.
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Re: Exponent algebra

by jayhawk2001 » Wed Feb 28, 2007 10:24 pm
Please post the source of your question.

I'm guessing the word missing here is "consecutive" positive integers,
in which case only 3*4 = 12 would make the cut. Else, it would be impossible to find out xy from just "positive integers" especially since
all the answers are products of 2 positive integers.


[quote="ash_maverick"]x and y are positive integers. , what is the value of xy?

(A) 48
(B) 36
(C) 24
(D) 18
(E) 12--ans

Please explain[/quote]
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