Arithmetic :: Manhattan GMAT Forums

Posted: Sat Dec 22, 2007 6:43 pm

Data Sufficiency question 146 in the orange GMAT Review book:

Is n an integer?

(1) n^2 (n squared) is an integer
(2) square root of n is an integer

The answer is B - statement 2 alone.

My question is - why is the answer not D? How can n^2 be an integer without n being an integer? This implies that a non-integer squared will give you an integer. What is an example of a fraction squared that results in an integer? I am not sure what I'm missing here.

Thanks,[/i][/b]

Posted: Sat Dec 22, 2007 7:24 pm

I just figured it out from a previous post. 1.4141... is an example, when squared would yield an integer. All prime numbers should have a non-integer square root...

Thanks anyway!

Posted: Sun Dec 23, 2007 1:23 am

n^2=3, then n is not an integer!!!

wgmast01 wrote:

Data Sufficiency question 146 in the orange GMAT Review book:

Is n an integer?

(1) n^2 (n squared) is an integer
(2) square root of n is an integer

The answer is B - statement 2 alone.

My question is - why is the answer not D? How can n^2 be an integer without n being an integer? This implies that a non-integer squared will give you an integer. What is an example of a fraction squared that results in an integer? I am not sure what I'm missing here.

Thanks,[/i][/b]

Posted: Mon Dec 24, 2007 1:32 pm

Excellent! I'm glad you figured it out on your own - that's the best way!