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:

1) no info about n (insuf) 2) n=7m/2. To make n an integer, m=2b (b is an pos integer). With b=1,2,3...we have varied GCD of m and n (insuf) Together we have m=2, n=7 GCD=1, suf

Re: What is the greatest common divisor of the positive integers [#permalink]
02 Mar 2012, 11:20

6

This post received KUDOS

Expert's post

2

This post was BOOKMARKED

What is the greatest common divisor of positive integers m and n?

(1) m is a prime number --> if m=2=prime and n=1 then GCD(m,n)=1 but if m=2=prime and n=4 then GCD(m,n)=2. Two different answers, hence not sufficient.

(2) 2n=7m --> \frac{m}{n}=\frac{2}{7} --> m is a multiple of 2 and n is a multiple of 7, but this is still not sufficient: if m=2 and n=7 then GCD(m,n)=1 (as both are primes) but if m=4 and n=14 then GCD(m,n)=2 (basically as \frac{m}{n}=\frac{2x}{7x} then as 2 and 7 are primes then GCD(m, n)=x). Two different answers, hence not sufficient.

(1)+(2) Since from (1) m=prime and from (2) \frac{m}{n}=\frac{2}{7} then m=2=prime and n=7, hence GCD(m,n)=1. Sufficient.

Re: What is the greatest common divisor of positive integers m [#permalink]
24 Sep 2012, 21:02

1) This statement says that M is Prime no, So N can be Prime/Composite. If N is Prime , clearly GCD will be 1, If N is composite also GCD will be 1( Except when M itself is a divisor of N, means N<>kM(not equals)), If N=kM then GCD(M,N) will be M it self.(where k is an integer)

2)2N=7M, its clearly not sufficient.

Combining:

From the statement 1, if we can get N=kM or not(where k is an integer) then we will be sure whats the GCD. As from the statement 2, we can see that N=7/2 M, and 7/2 is not an integer. So clearly GCD will be 1.

Re: What is the greatest common divisor of the positive integers [#permalink]
24 Sep 2013, 10:07

Bunuel wrote:

What is the greatest common divisor of positive integers m and n?

(1) m is a prime number --> if m=2=prime and n=1 then GCD(m,n)=1 but if m=2=prime and n=4 then GCD(m,n)=2. Two different answers, hence not sufficient.

(2) 2n=7m --> \frac{m}{n}=\frac{2}{7} --> m is a multiple of 2 and n is a multiple of 7, but this is still not sufficient: if m=2 and n=7 then GCD(m,n)=1 (as both are primes) but if m=4 and n=14 then GCD(m,n)=2 (basically as \frac{m}{n}=\frac{2x}{7x} then as 2 and 7 are primes then GCD(m, n)=x). Two different answers, hence not sufficient.

(1)+(2) Since from (1) m=prime and from (2) \frac{m}{n}=\frac{2}{7} then m=2=prime and n=7, hence GCD(m,n)=1. Sufficient.

Answer: C.

Greatest Common divisor and Highest common factor are same thing Bunuel?

Because n= 7m/2 (Taking both this is true only for m = 2) So Greatest common divisor is 2 not 1, Isn't it? _________________

Re: What is the greatest common divisor of the positive integers [#permalink]
24 Sep 2013, 14:12

Expert's post

honchos wrote:

Bunuel wrote:

What is the greatest common divisor of positive integers m and n?

(1) m is a prime number --> if m=2=prime and n=1 then GCD(m,n)=1 but if m=2=prime and n=4 then GCD(m,n)=2. Two different answers, hence not sufficient.

(2) 2n=7m --> \frac{m}{n}=\frac{2}{7} --> m is a multiple of 2 and n is a multiple of 7, but this is still not sufficient: if m=2 and n=7 then GCD(m,n)=1 (as both are primes) but if m=4 and n=14 then GCD(m,n)=2 (basically as \frac{m}{n}=\frac{2x}{7x} then as 2 and 7 are primes then GCD(m, n)=x). Two different answers, hence not sufficient.

(1)+(2) Since from (1) m=prime and from (2) \frac{m}{n}=\frac{2}{7} then m=2=prime and n=7, hence GCD(m,n)=1. Sufficient.

Answer: C.

Greatest Common divisor and Highest common factor are same thing Bunuel?

Because n= 7m/2 (Taking both this is true only for m = 2) So Greatest common divisor is 2 not 1, Isn't it?

Yes, GCD and GCF are the same thing.

But couldn't understand your second point: the greatest common divisor of 2 and 7 is 1. How can it be 2? Is 7 divisible by 2? _________________

Re: What is the greatest common divisor of positive integers m [#permalink]
16 Nov 2014, 06:14

Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email. _________________

My three goals of business school: entrepreneurship, network, and professor mentor. I want to build something. I want to meet new people and create life-long friendships. I want to...