GMAT Prep2?? (Divisible by 3)

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Source: — Data Sufficiency |

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by akshatsingh » Wed May 14, 2008 9:44 pm
B is sufficient.
Aks

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by reetchatha » Fri May 16, 2008 9:08 am
144/n^2 can be 144/2^2 or 144/3^2 where n can be 2 or 3 then how is b sufficient? Am i missing anything here?

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by aatech » Fri May 16, 2008 9:19 am
Stmt 1 - put n=2 => 4 is not divisble. Put n=3 => 9 is divisible by 3 NOT SUFF

Stmt 2 -

144 = 2*2*2*2*3*3

Since 144/n^2 is an integer than means n can be 2,3 or 4. 3 is divisble by 3. 2 and 4 are not.

NOT SUFF

Together NOT SUFF as n can be 2,3 or 4

IMO E. OA?

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by dferm » Fri May 16, 2008 10:15 am
answer IS A....

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by aatech » Fri May 16, 2008 10:22 am
How reliable is the source of this question?

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by dferm » Fri May 16, 2008 10:45 am
Very reliable since it come from the GMAT PREP...

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by dferm » Fri May 16, 2008 10:57 am
Sorry Guys..

The question wasn't written correctly..

Is positive integer n divisible by 3?

(1) n^2/36 is an integer
(2) 144/n^2 is an integer

This is the correct question..

Sorry for the inconvenience.....

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by aatech » Fri May 16, 2008 11:01 am
Hmmm... That makes sense.. ANS would be A

n^2/36 is an integer that means n is divisible by 6 (3*2)

=> n is divisible by 3 SUFF

Stmt 2 - NOT SUFF -- my earlier explanation stands

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by mim3 » Mon May 19, 2008 12:43 pm
aatech wrote:Hmmm... That makes sense.. ANS would be A

n^2/36 is an integer that means n is divisible by 6 (3*2)

=> n is divisible by 3 SUFF

Stmt 2 - NOT SUFF -- my earlier explanation stands
Agreed- it's A.

1. n^2/36 is an integer
n^2 always going to be a multiple of 36. The only squares that are divisble by 36 are multiples of 6: 6^2. 12^2, 18^2, ect... so n is divisble by 3. Sufficient.

2. 144/n^2 is an integer- n could be either 12 (144/144= 1) or 4 (144/16= 9). Insufficient.