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 350,000 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:

How many prime factors does positive integer N have? (1) N/5 [#permalink]
28 Jul 2008, 01:33

. How many prime factors does positive integer N have? (1) N/5 is a prime number. (2) 3N^2 has two different prime factors A. Statement (1) ALONE is sufficient but Statement (2) ALONE is not sufficient. B. Statement (2) ALONE is sufficient but Statement (1) ALONE is not sufficient. C. BOTH Statements TOGETHER are sufficient, but NEITHER Statement alone is sufficient. D. Each Statement ALONE is sufficient.. E. Statements (1) and (2) TOGETHER are NOT sufficient..

Last edited by arjtryarjtry on 28 Jul 2008, 05:10, edited 1 time in total.

Re: prime factors how many [#permalink]
28 Jul 2008, 02:52

Stmt 1: Insufficient. For example, if N = 10, its factors are 1, 2, 5 and 10. If N = 15, its factors are 1, 3,5 an If N = 20, then factors are 1, 2, 4, 5, 10 and 20.

Re: prime factors how many [#permalink]
28 Jul 2008, 04:42

arjtryarjtry wrote:

. How many prime factors does positive integer N have? (1) N/5 is a prime number. (2) 3N^2 has two different prime number. A. Statement (1) ALONE is sufficient but Statement (2) ALONE is not sufficient. B. Statement (2) ALONE is sufficient but Statement (1) ALONE is not sufficient. C. BOTH Statements TOGETHER are sufficient, but NEITHER Statement alone is sufficient. D. Each Statement ALONE is sufficient.. E. Statements (1) and (2) TOGETHER are NOT sufficient..

(1) - N/5 is a prime number. from this, we know that 5 is a factor of N

two options i) N has only one prime factor (N/5 can be = 5 (if N = 25), ii) N has only two prime factor (N/5 = another prime number (if N <> 25)

therefore insuff

(2) 3N^2 has two different prime number two different options i) N^2 has only one prime factor (3 not a factor of N) i) N^2 has only two prime factors (3 is a factor of N)

combining the two, we still dont know how many factors are there. therefore E

PS : N = 25 (N^2 = 625) and N = 15 (N^2 = 225) both satisfy the above conditions.

Last edited by sset009 on 28 Jul 2008, 05:14, edited 1 time in total.

Re: prime factors how many [#permalink]
28 Jul 2008, 05:10

i thought the ans as B COS, 3N^2 has two DIFF factors -> N^2 has one factor. so it should be suff ... i think. eg 3*25 has 2 diff factors, also 3*49.has 2 diff factors. but we cant take 3*81, together they contain only 1 prime factor i.e 3 .

Re: prime factors how many [#permalink]
28 Jul 2008, 05:13

arjtryarjtry wrote:

i thought the ans as B COS, 3N^2 has two DIFF factors -> N^2 has one factor. so it should be suff ... i think. eg 3*25 has 2 diff factors, also 3*49.has 2 diff factors. but we cant take 3*81, together they contain only 1 prime factor i.e 3 .

what bout if N = 15 then 3*(N^2) has two different prime numbers, and N has two different prime numbers

Re: prime factors how many [#permalink]
28 Jul 2008, 07:37

arjtryarjtry wrote:

. How many prime factors does positive integer N have? (1) N/5 is a prime number. (2) 3N^2 has two different prime factors A. Statement (1) ALONE is sufficient but Statement (2) ALONE is not sufficient. B. Statement (2) ALONE is sufficient but Statement (1) ALONE is not sufficient. C. BOTH Statements TOGETHER are sufficient, but NEITHER Statement alone is sufficient. D. Each Statement ALONE is sufficient.. E. Statements (1) and (2) TOGETHER are NOT sufficient..

(1) alone sufficient. because it tells us the N is the product of 5 and the other prime number (factor).

(2) alone is Not Suff. if N = 6, 3N^2 have 2 different prime factors, i.e. 3 and 2, and N also has 2 different prime factors, also 3 and 2. if N = 2, 3N^2 have two different prime factors, i.e. 3 and 2, BUT N has ONLY 1 prime factor, which is 2.

Re: prime factors how many [#permalink]
28 Jul 2008, 07:38

sset009 wrote:

arjtryarjtry wrote:

. How many prime factors does positive integer N have? (1) N/5 is a prime number. (2) 3N^2 has two different prime number. A. Statement (1) ALONE is sufficient but Statement (2) ALONE is not sufficient. B. Statement (2) ALONE is sufficient but Statement (1) ALONE is not sufficient. C. BOTH Statements TOGETHER are sufficient, but NEITHER Statement alone is sufficient. D. Each Statement ALONE is sufficient.. E. Statements (1) and (2) TOGETHER are NOT sufficient..

(1) - N/5 is a prime number. from this, we know that 5 is a factor of N

two options i) N has only one prime factor (N/5 can be = 5 (if N = 25), ii) N has only two prime factor (N/5 = another prime number (if N <> 25)

therefore insuff

(2) 3N^2 has two different prime number two different options i) N^2 has only one prime factor (3 not a factor of N) i) N^2 has only two prime factors (3 is a factor of N)

combining the two, we still dont know how many factors are there. therefore E

PS : N = 25 (N^2 = 625) and N = 15 (N^2 = 225) both satisfy the above conditions.

You are right, good explanation, thanks

gmatclubot

Re: prime factors how many
[#permalink]
28 Jul 2008, 07:38

How the growth of emerging markets will strain global finance : Emerging economies need access to capital (i.e., finance) in order to fund the projects necessary for...

One question I get a lot from prospective students is what to do in the summer before the MBA program. Like a lot of folks from non traditional backgrounds...