Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized for You

we will pick new questions that match your level based on your Timer History

Track Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

It appears that you are browsing the GMAT Club forum unregistered!

Signing up is free, quick, and confidential.
Join other 500,000 members and get the full benefits of GMAT Club

Registration gives you:

Tests

Take 11 tests and quizzes from GMAT Club and leading GMAT prep companies such as Manhattan GMAT,
Knewton, and others. All are free for GMAT Club members.

Applicant Stats

View detailed applicant stats such as GPA, GMAT score, work experience, location, application
status, and more

Books/Downloads

Download thousands of study notes,
question collections, GMAT Club’s
Grammar and Math books.
All are free!

Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:

Is the positive integer P a prime number? [#permalink]

Show Tags

18 Aug 2014, 07:38

1

This post was BOOKMARKED

For Stat1 P can be equal to 3 and can be equal to 9. So not sufficient

For STAT2 P can be equal to 7 and can be equal to 9. So not sufficient

STAT1 and STAT2 together p-4, p-2,p, p+2, p+4 If P is prime then P must be odd (as only even prime is 2 and p-4 will not be prime then) if p is odd then p cannot be prime as p-4,p-2,p,p+2,p+4 make a series of 5 consecutive odd numbers and NO pair of 5 consecutive odd numbers are prime

(1) (P+2) and (P+4) are prime. If p = 1, then the answer is NO but if p = 3, then the answer is YES. Not sufficient.

(2) (P-2) and (P-4) are prime. If p = 9, then the answer is NO but if p = 7, then the answer is YES. Not sufficient.

(1)+(2) Since (P-4), (P-2), (P+2), and (P+4) are primes, then all of them must be odd numbers. This means that (P-4), (P-2), P, (P+2), and (P+4) are 5 consecutive odd numbers. Since there are no 5 consecutive odd primes, then P cannot be a prime (out of 5 consecutive odd numbers one must be a multiple of 3 and another a multiple of 5. There are only one prime, which is a multiple of 3, 3 itself and there are only one prime, which is a multiple of 5, 5 itself but P can be neither 3 or 5 since this violate (P-4), (P-2), (P+2), and (P+4) being primes). Sufficient.

For Stat1 P can be equal to 2 and can be equal to 9. So not sufficient

For STAT2 P can be equal to 7 and can be equal to 9. So not sufficient

STAT1 and STAT2 together p-4, p-2,p, p+2, p+4 If P is prime then P must be odd (as only even prime is 2 and p-4 will not be prime then) if p is odd then p cannot be prime as p-4,p-2,p,p+2,p+4 make a series of 5 consecutive odd numbers and NO pair of 5 consecutive odd numbers are prime

So, p is NOT a prime number. So, Answer will be C

Hope it helps!

One little correction. P cannot be 2, since in this case neither P+2 nor P+4 is a prime.
_________________

Re: Is the positive integer P a prime number? [#permalink]

Show Tags

18 Aug 2014, 08:14

Thanks Bunuel, Wanted to write 3 (edited)

Bunuel wrote:

nktdotgupta wrote:

For Stat1 P can be equal to 2 and can be equal to 9. So not sufficient

For STAT2 P can be equal to 7 and can be equal to 9. So not sufficient

STAT1 and STAT2 together p-4, p-2,p, p+2, p+4 If P is prime then P must be odd (as only even prime is 2 and p-4 will not be prime then) if p is odd then p cannot be prime as p-4,p-2,p,p+2,p+4 make a series of 5 consecutive odd numbers and NO pair of 5 consecutive odd numbers are prime

So, p is NOT a prime number. So, Answer will be C

Hope it helps!

One little correction. P cannot be 2, since in this case neither P+2 nor P+4 is a prime.

Happy New Year everyone! Before I get started on this post, and well, restarted on this blog in general, I wanted to mention something. For the past several months...

It’s quickly approaching two years since I last wrote anything on this blog. A lot has happened since then. When I last posted, I had just gotten back from...

Happy 2017! Here is another update, 7 months later. With this pace I might add only one more post before the end of the GSB! However, I promised that...

The words of John O’Donohue ring in my head every time I reflect on the transformative, euphoric, life-changing, demanding, emotional, and great year that 2016 was! The fourth to...