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fernandonefro
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 Posted: Mon Aug 13, 2007 7:36 pm Post subject: Official Guide Orange Data Sufficiency #146 |
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Is n an interger?
(1)n to the power of 2 is an interger
(2)The root of n is an interger
Anybody knows how to explain the (1) better than the Oficcial Guide?
I did not understand... |
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ratindasgupta
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| Posted: Tue Aug 14, 2007 12:47 am Post subject: Re: Official Guide Orange Data Sufficiency #146 |
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| fernandonefro wrote: | Is n an interger?
(1)n to the power of 2 is an interger
(2)The root of n is an interger
Anybody knows how to explain the (1) better than the Oficcial Guide?
I did not understand... |
the answer is B.
n to the power of 2 is basically n^2. If n^2 is an integer, it doesnt necessarily mean that n is an integer. Eliminate (1)
If root of n is an integer, then n will also be an integer. |
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givemeanid
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| Posted: Tue Aug 14, 2007 5:24 am Post subject: Re: Official Guide Orange Data Sufficiency #146 |
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| fernandonefro wrote: | Is n an interger?
(1)n to the power of 2 is an interger
(2)The root of n is an interger
Anybody knows how to explain the (1) better than the Oficcial Guide?
I did not understand... |
1. n*n = an integer.
If n*n = 4, n = 2 or -2 and is an integer.
However, n can be sqrt(2). Then n*n = sqrt(2) * sqrt(2) = 2 = an integer. But sqrt(2) is not an integer.
NOT SUFFICIENT.
2. sqrt(n) = integer
If you square both side, n = square of an integer.
Square of an integer is always an integer since you are multiplying two integers.
SUFFICIENT.
Answer is B.
Also, when you are in doubt, try to post what part of a concept/problem you do not understand. That way, somebody can elaborate on that specific point with more detail.
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bsdf78
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| Posted: Sun Jul 20, 2008 11:41 am Post subject: thanks! |
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| thank you for this answer!! i fogot the n could be = the square root of a number. was killing me. |
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