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If (1/5)^m x (1/4)^18 = 1/(2x10^35), then m=?

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agalstia
 Post subject: If (1/5)^m x (1/4)^18 = 1/(2x10^35), then m=?
 Post Posted: Thu Sep 23, 2010 11:38 pm 
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Course Students


Posts: 12
If (1/5)^m x (1/4)^18 = 1/(2x10^35), then m=?

A) 17
B) 18
C) 34
D) 35
E) 36


OA is D

I tried doing this problem several times in several different ways. I first attempted to split the 10 on the right side into its factors of 2 and 5. I also split the 4 on the rights into its factors of 2x2. However, I was clueless as to how I could combine the fractions, so just ended up guessing A and got it wrong. Please help.
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gokul_nair1984
 Post subject: Re: If (1/5)^m x (1/4)^18 = 1/(2x10^35), then m=?
 Post Posted: Fri Sep 24, 2010 12:31 am 
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Students


Posts: 170
there you go:

http://www.manhattangmat.com/forums/gmat-prep-1-5-m-1-4-18-1-2-10-35-t1976.html
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agalstia
 Post subject: Re: If (1/5)^m x (1/4)^18 = 1/(2x10^35), then m=?
 Post Posted: Fri Sep 24, 2010 12:46 am 
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Course Students


Posts: 12
Thanks! I had tried searching it, but it wasn't coming up anywhere.
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vinamragharat
 Post subject: Re: If (1/5)^m x (1/4)^18 = 1/(2x10^35), then m=?
 Post Posted: Sat Sep 25, 2010 3:20 am 
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Students


Posts: 1
Location: India, Mumbai
M=35

Here how it goes,
1/(2x2^35x5^35) = 1/5^m x 1/2^36 (since 1/4^18 = 1/2^36)

Now, we have same BASE, so we can ADD the powers.Therefore,

1/(2^36 x 5^35) = 1/2^36 x 1/5^m

compare. We get,

1/5^m = 1/5^35

M=35


Please refer to MGMAT Guides! They are awesome on this stuff!
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RonPurewal
 Post subject: Re: If (1/5)^m x (1/4)^18 = 1/(2x10^35), then m=?
 Post Posted: Mon Oct 04, 2010 8:45 am 
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ManhattanGMAT Staff


Posts: 7146
guys, when someone posts a link to an already existing thread, please post all subsequent comments on that thread, not this one. we don't want a bunch of concurrent threads running on the same problem.

we will henceforth delete all new comments on this thread; if you have anything else to say about this problem, please post it on the thread referred above.

thanks.
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