prob solving

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prob solving

by ssraf » Sun Jun 08, 2008 7:03 pm
what is the smallest integer n for which 25^n > 5^12?

a)6
b)7
c)8
d)9
e)10

OA is 7. Can someone help with the reasoning behind this? I tried a similar scenario ala 36 and 6 (ss base) with no luck....

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by netigen » Sun Jun 08, 2008 8:39 pm
25^n = 5^(2n)

which means 2n > 12 or n>6