Is n divisible by 30?

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Is n divisible by 30?

by RadiumBall » Sun Mar 20, 2011 4:34 am
if n^2/n yields an integer greater than 0, is n divisible by 30?

(1) n^2 is divisible by 20
(2) n^3 is divisible by 12

I would like to know a generic approach to such problems where in operation related to 'n' is asked but information provided is related to powers of 'n'.

Thanks
Source: — Data Sufficiency |

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by Anurag@Gurome » Sun Mar 20, 2011 6:27 am
RadiumBall wrote:if n^2/n yields an integer greater than 0, is n divisible by 30?

(1) n^2 is divisible by 20
(2) n^3 is divisible by 12
"If n²/n yields an integer greater than 0" implies n is a positive integer!

Statement 1: n² is divisible by 20 = 4*5 = (2²)*5
Implies n is divisible by 2 and 5.
But no information whether n is divisible by 3 or not.

Not sufficient

Statement 2: n³ is divisible by 12 = 3*4 = 3*(2²)
Implies n is divisible by 2 and 3.
But no information whether n is divisible by 5 or not.

Not sufficient

1 & 2 Together: n is divisible by 2, 3, and 5.

Sufficient

The correct answer is C.
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by RadiumBall » Sun Mar 20, 2011 8:50 pm
Wow...superb...Thanks.