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:

Re: The LCM of three numbers is four times their GCF. Which of [#permalink]
12 Mar 2013, 20:29

3

This post received KUDOS

Expert's post

avinashrao9 wrote:

Hi Bunuel,

Is there any general approach to solve this problem?? Finding a set of 3 numbers might be difficult somtimes

Consider a generic approach. LCM - L GCF - G L = 4*G

The numbers must be of the form: Gn, Gm, Gk. Since other than G, L contains only 4, n, m and k must be of one of the three numbers: 1, 2, 4

Mind you, there must be one number which is G because otherwise, the GCF will change. GCF of 2G, 2G, 4G will be 2G, not G. There must be one number which is 4G because otherwise, the LCM will change. LCM of G, 2G, 2G is 2G, not 4G

So the three numbers could be of the form: G, 2G, 4G or G, G, 4G or G, 4G, 4G

If G is even, no number will be odd. Hence I and II needn't be true. III must be true.

Re: The LCM of three numbers is four times their GCF. Which of [#permalink]
27 Mar 2013, 13:09

VeritasPrepKarishma wrote:

avinashrao9 wrote:

Hi Bunuel,

Is there any general approach to solve this problem?? Finding a set of 3 numbers might be difficult somtimes

Consider a generic approach. LCM - L GCF - G L = 4*G

The numbers must be of the form: Gn, Gm, Gk. Since other than G, L contains only 4, n, m and k must be of one of the three numbers: 1, 2, 4

Mind you, there must be one number which is G because otherwise, the GCF will change. GCF of 2G, 2G, 4G will be 2G, not G. There must be one number which is 4G because otherwise, the LCM will change. LCM of G, 2G, 2G is 2G, not 4G

So the three numbers could be of the form: G, 2G, 4G or G, G, 4G or G, 4G, 4G

If G is even, no number will be odd. Hence I and II needn't be true. III must be true.

Answer (B)

Hi karishma, I could not understand anything out of this explanation. Could you please explain it to me in a more detailed manner??

Re: The LCM of three numbers is four times their GCF. Which of [#permalink]
25 Dec 2013, 17:28

1

This post was BOOKMARKED

Jlgdr,

I guess what Karishma is saying is this :

G*N, G*M, G*K are the 3 numbers whose GCF is G. LCM of these 3 numbers can be written as LCM(G*N,G*M,G*K) = G*LCM(N,M,K) = 4 *G (given). So LCM(N,M,K) = 4. This would mean {N,M,K} can be {1,1,4} or {1,2,4} or {1,4,4} since the LCM of the 3 numbers is 4. So the only possible solution is number B.

Re: The LCM of three numbers is four times their GCF. Which of [#permalink]
03 May 2015, 11:12

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. _________________

The Importance of Financial Regulation : Before immersing in the technical details of valuing stocks, bonds, derivatives and companies, I always told my students that the financial system is...

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...