prime numbers are factors

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prime numbers are factors

by sanju09 » Fri Sep 17, 2010 2:56 am
How many different prime numbers are factors of the positive integer n?

[1] Four different prime numbers are factors of 2 n.

[2] Four different prime numbers are factors of n^2.


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by Fiver » Fri Sep 17, 2010 7:10 am
How many different prime factors contribute to the form the positive integer n ?

St1] Four different prime numbers are factors of 2 n.
This means that the prime number 2 either could be a part of 'n' itself, yeilding 4 as the answer or could not be a part of 'n' yeilding 3 as the answer. Insuff.

St2] Four different prime numbers are factors of n^2.
If 4 different prime numbers make up n^2, then all 4 must be present in 'n' as well. Suff.

I pick B.

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by sanju09 » Fri Sep 17, 2010 8:09 pm
Fiver wrote:How many different prime factors contribute to the form the positive integer n ?

St1] Four different prime numbers are factors of 2 n.
This means that the prime number 2 either could be a part of 'n' itself, yeilding 4 as the answer or could not be a part of 'n' yeilding 3 as the answer. Insuff.

St2] Four different prime numbers are factors of n^2.
If 4 different prime numbers make up n^2, then all 4 must be present in 'n' as well. Suff.

I pick B.
very good shot Fiver
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