prime number question

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prime number question

by Baldini » Fri Mar 06, 2009 6:16 am
If p is a prime number greater than 2, what is the value of p?

(1) there are a total of 100 prime numbers between 1 and p+1
(2) there are a total of p prime numbers between 1 and 3912

OA is D

Can someone explain how to work this out please^?
GMAX

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by praxis » Fri Mar 06, 2009 6:47 am
Remember, you don't need to calculate p, only to know that it would be possible to calculate p!

(1) You could create a list of prime numbers; p is the 100th prime. This is sufficient.

(2) You could create a list of all prime numbers less than 3912. Then you could count them, and that number would be p. This is sufficient.

So each statement is sufficient by itself.

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