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OG11 - sanity check...

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OG11 - sanity check...

by Sadowski » Tue May 22, 2007 11:55 am
Does it strike anyone else that the wording of this question will leave you with a number that's not available among the answer choices?

If n=4p, where p is a prime number greater than 2, how many different positive even divisors does n have, including n?

a) 2
b) 3
c) 4
d) 6
e) 8
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by 800GMAT » Tue May 22, 2007 1:47 pm
I chose 3 as another prime number greater than 2 and got 4 as the number of divisors including 12

C
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by Sadowski » Tue May 22, 2007 5:40 pm
As I read your post, I realized what my mistake was.

Regardless of the prime number, we should be able to divide 4p by 2, 4, 2p, and 4p.

For some reason, I was wanting to add n to that list of 4 divisors, making it 5 total, but of course n=4p is already on the list :oops:

Stupid mistake!
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by Cybermusings » Tue May 22, 2007 10:03 pm
Since p is prime, p will have only 2 factors p and 1 (however both are odd, since p is a prime number greater than 2)
4 has 3 factors (1,2 & 4)
n is an even number...hence 4p will have 4 even divisors (4,2, 2p and n)
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