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Number properties??

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Number properties??

by fruti_yum » Mon Aug 03, 2009 1:05 pm
Is 12 a factor of the positive integer n?
(1) n is a factor of 36.
(2) 3 is a factor of n


I get that A is sufficient ..

n is a factor of 36 implies 36/n = integer
n has to have 2,2,3,3 in it's prime factor box..

therefore, n definitely has 2,2,3 to be a factor of 12

however, the oa is E... Can someone explain??
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Source: — Data Sufficiency |
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by ssmiles08 » Mon Aug 03, 2009 1:23 pm
Another way of stating the question: is n/12 = integer?

1) 36/n = integer

n can be 3, 2, 12, 36...

Insufficient.

2) n/3 = integer

n can be 3, 6, 12...

Insufficient

Together: n can still be 3, 6, 12, 36...

Insufficient

(E)

EDIT: I think you are confusing 36/n with n/36.

n/36 means 2,2,3,3 have to be in n's prime box
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Re: Number properties??

by shahdevine » Mon Aug 03, 2009 1:37 pm
fruti_yum wrote:Is 12 a factor of the positive integer n?
(1) n is a factor of 36.
(2) 3 is a factor of n


I get that A is sufficient ..

n is a factor of 36 implies 36/n = integer
n has to have 2,2,3,3 in it's prime factor box..

therefore, n definitely has 2,2,3 to be a factor of 12

however, the oa is E... Can someone explain??

retranslate question --> does N have at least two 2s and one 3 in it?

statement 1)

n is a factor of 36 means that n could have a 2,3, 4, 9, 12, 36 in it? n could be 12 but necessarily so insufficient.

statement 2)

3 is a factor of n means that n at least has one 3. But this is insufficient because we don't know if n also has the two 2s we need.

Combine..

When we combine again we know that n has at least a 3 but we don't know if its other factors are two 2s. Therefore insufficient.

E

you got this!!!
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