Integer

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Integer

by ricky » Sun Jul 13, 2008 3:05 am
Please help me on the following Data sufficiency question...

Is n an integer?

1)n^2 is an integer.

2)n^1/2 is an integer.


Thanx
Source: — Data Sufficiency |

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by anubhavmehrotra » Sun Jul 13, 2008 4:24 am
This is an OG question... answer B... consider plugging in values 2 and 4 for each statement.

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by ricky » Sun Jul 13, 2008 6:06 am
But for the 1st statement; if a number's square is an integer then the number shoud be integer as well.
Why cant the answer be D?
Thanx

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by lion147 » Sun Jul 13, 2008 3:16 pm
ricky wrote:But for the 1st statement; if a number's square is an integer then the number shoud be integer as well.
Why cant the answer be D?
Thanx
Because for statement 1 n could be the sroot(2), sroot(3), sroot(5) etc...

For statement 2 - sroot(n) is an integer, therefore n must be a perfect square.