Prime Nos.

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Spartacus2000: Junior | Next Rank: 30 Posts; Posts: 26; Joined: Sun May 01, 2011 2:31 pm

Prime Nos.

by Spartacus2000 » Tue Aug 09, 2011 6:46 pm

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 3,912

Thanks

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Source: Beat The GMAT — Data Sufficiency | Tue Aug 09, 2011 6:46 pm

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Anurag@Gurome: GMAT Instructor; Posts: 3835; Joined: Fri Apr 02, 2010 10:00 pm; Location: Milpitas, CA; Thanked: 1854 times; Followed by:523 members; GMAT Score:770

by Anurag@Gurome » Tue Aug 09, 2011 8:59 pm

Spartacus2000 wrote: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 3,912

Thanks

(1) We can write the first 100 prime numbers. It is given that there are 100 prime numbers between 1 and p + 1, so p is the 100th prime number; SUFFICIENT.

(2) We can write all prime numbers between 1 and 3912 and count these numbers; SUFFICIENT.

The correct answer is D.

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ArpanaAmishi: Senior | Next Rank: 100 Posts; Posts: 93; Joined: Sun Jun 06, 2010 10:52 pm; Thanked: 2 times; Followed by:1 members

by ArpanaAmishi » Tue Aug 09, 2011 11:00 pm

Anurag@Gurome wrote:
Spartacus2000 wrote: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 3,912

Thanks
(1) We can write the first 100 prime numbers. It is given that there are 100 prime numbers between 1 and p + 1, so p is the 100th prime number; SUFFICIENT.

(2) We can write all prime numbers between 1 and 3912 and count these numbers; SUFFICIENT.

The correct answer is D.

Hi Anurag,
Please elaborate on 2nd statment..I think question is looking for value of P not the counting.

Quote

GMAT/MBA Expert

Anurag@Gurome: GMAT Instructor; Posts: 3835; Joined: Fri Apr 02, 2010 10:00 pm; Location: Milpitas, CA; Thanked: 1854 times; Followed by:523 members; GMAT Score:770

by Anurag@Gurome » Tue Aug 09, 2011 11:03 pm

ArpanaAmishi wrote:
Anurag@Gurome wrote:
Spartacus2000 wrote: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 3,912

Thanks
(1) We can write the first 100 prime numbers. It is given that there are 100 prime numbers between 1 and p + 1, so p is the 100th prime number; SUFFICIENT.

(2) We can write all prime numbers between 1 and 3912 and count these numbers; SUFFICIENT.

The correct answer is D.
Hi Anurag,
Please elaborate on 2nd statment..I think question is looking for value of P not the counting.

Statement 2 says "There are a total of p prime numbers between 1 and 3,912", which means if we count all the prime numbers between 1 and 3,912, then that will be the value of p. Hence, SUFFICIENT.

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GmatKiss: Legendary Member; Posts: 2789; Joined: Tue Jul 26, 2011 12:19 am; Location: Chennai, India; Thanked: 206 times; Followed by:43 members; GMAT Score:640

by GmatKiss » Wed Aug 10, 2011 3:25 am

IMO:D

(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 3,912

Both gives us a particular range, hence p can be found!