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Equation Gmatprep

by pepeprepa » Thu Aug 07, 2008 6:59 am
For how many integers, n is 2^n=n^2 ?
A) 2
B) 3
C) 4
D) 5
E) none

I couldn't find the old post.


I did it by drawing a graph, can someone make it with calculations?
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by sudhir3127 » Thu Aug 07, 2008 7:11 am
i would say A..

only 2 numbers satisfy the equation 2 and 4

2^n=n^2

2^2 = 2^2

4^2 = 2^4..

hope its helps...
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by pepeprepa » Thu Aug 07, 2008 8:25 am
You are right that's 2 but we cannot be totally sure by looking at numbers...
What confused me with my graph was that there is an intersection between the two equations between 0 and -1 but that is not an integer so the answer is 2.
Thanks!
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by Xbond » Thu Aug 07, 2008 9:42 am
what is OA, please ?
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by pepeprepa » Thu Aug 07, 2008 9:48 am
pepeprepa wrote:You are right that's 2 but we cannot be totally sure by looking at numbers...
What confused me with my graph was that there is an intersection between the two equations between 0 and -1 but that is not an integer so the answer is 2.
Thanks!
Answer is probably 2 :wink:
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