Integer

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Integer

by irock » Sat May 28, 2011 11:22 pm
If sq. root n is a positive integer, what is the value of n?
(1) 1 < sq. root n <5
(2) l0 < n < 24

Answer: B
Source: — Data Sufficiency |

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by Stuart@KaplanGMAT » Sat May 28, 2011 11:36 pm
irock wrote:If sq. root n is a positive integer, what is the value of n?
(1) 1 < sq. root n <5
(2) l0 < n < 24

Answer: B
Hi!

Let's start by analyzing the question stem. If sqrt(n) is a positive integer, then n is a perfect square, e.g. 1, 4, 9, 16, ... We want to know the exact value of n.

(1) we know that sqrt(n) is an integer between 1 and 5. So, sqrt(n) could be 2, 3 or 4. Each of those gives us a different value for n: insufficient.

(2) we know that n is perfect square between 10 and 24. The only perfect square in that range is 16, so n MUST be 16: sufficient.

(2) is sufficient, (1) is insufficient - choose (B)!
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by sandeep800 » Sun May 29, 2011 3:38 am
Wooww Thanx Stuart.
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by irock » Sun May 29, 2011 8:26 pm
thanks stuart..