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by rishi235 » Wed Aug 27, 2008 7:57 am
5^21 x 4^11= 2 x 10^n
Now 2 x 10^n = 2*5^n*n^n = 2^(n+1)*5^n
Equate with LHS....
U'll get n=21
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by b.kurland » Wed Aug 27, 2008 2:18 pm
the trick is knowing that (a^n)(b^n)=ab^n. so...

4^11 = 2^22 = 2(2^21)
(5^21)(2^21)(2) = 2(10^n)
2(10^21) = 2(10^n)
n=21 woot woot!
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