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:

Re: If an integer n is divisible by both 6 and 8, then it must [#permalink]

Show Tags

05 Jul 2007, 06:07

GK_Gmat wrote:

Amit05 wrote:

If an integer n is divisible by both 6 and 8, then it must also be divisible by which of the following? (A) 10 (B) 12 (C) 14 (D) 16 (E) 18

Though I got the correct ans by brute force. Just wondering which math rule could be applied here.

The way I figure it is taking the product of the prime factors which are not common among the two.

6= 3*2 8= 2*2*2

prod. of prime factors not common = 2*2*3=12

Answer B

I like this explanation. If it's divisible by 6, it must have every prime 6 has, and the same thing is true for 8. So there must be 2,2,3. Even if you don't find the lowest common multiple, as in above, you should still just look for the answers with just some 2's and one 3. 12 is the only one.

Note that 18 doesn't work because there's an extra 3 in it.

Last edited by ian7777 on 05 Jul 2007, 08:12, edited 1 time in total.

Re: If an integer n is divisible by both 6 and 8, then it must [#permalink]

Show Tags

14 Feb 2015, 15:47

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.
_________________

In these sorts of situations, prime-factorization is a great technical approach to get to the correct answer. There is another method that is actually pretty easy though - we can TEST VALUES. Since the prompt asks for what N MUST be divisible by, we just need to start with the SMALLEST positive integer for N that is DIVISIBLE by BOTH 6 and 8.

Many Test Takers would say that 48 is the smallest integer, but it's NOT. The smallest integer is actually 24. Here's proof that's fairly easy to put together....

Multiples of 6: 6, 12, 18, 24 Multiples of 8: 8, 16, 24

Re: If an integer n is divisible by both 6 and 8, then it must [#permalink]

Show Tags

24 Feb 2016, 17:55

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.
_________________

Re: If an integer n is divisible by both 6 and 8, then it must [#permalink]

Show Tags

27 May 2016, 05:45

Amit05 wrote:

If an integer n is divisible by both 6 and 8, then it must also be divisible by which of the following?

(A) 10 (B) 12 (C) 14 (D) 16 (E) 18

A very straightforward method involving the LCM exists to solve the problem.

First of all, "n" is divisible by both 6 and 8; This implies "n" is a Multiple of both 6 and 8.

Finding the LCM helps as all other Multiples of 6 and 8 may have extra prime factors which may lead to "n" be divisible by other numbers.

e.g. the LCM of 6 and 8 is 24, but if we find any multiple of 6 and 8 such as 48 or 72 then apart from 12, the number 48 is also divisible by 16 and 72 by 18.

Finally, check the divisiblity of the LCM by the options provided. Only one value should satisfy the divisibility condition.

Cheers!!!... Press "Kudos" if you liked the explanation.
_________________

Re: If an integer n is divisible by both 6 and 8, then it must [#permalink]

Show Tags

01 Sep 2017, 03:53

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.
_________________

If an integer n is divisible by both 6 and 8, then it must [#permalink]

Show Tags

02 Sep 2017, 08:57

n is divisible by both 6 and 8 means .... n = 6*8

n = 6*8 = (2^4) * 3 implies that the answer must meet two conditions: (1) be divisible by the product of its prime which is 6=2*3. This by itself narrows down the answer to B=12 or E=18. (2) contains at most one 3 and at most four 2's. E is not correct because it factors into two 3's which is one too many 3's.

If an integer n is divisible by both 6 and 8, then it must also be divisible by which of the following?

(A) 10 (B) 12 (C) 14 (D) 16 (E) 18

Let’s first find the LCM of 6 and 8. The prime factorization of 6 is 3 x 2 and the prime factorization of 8 is 2 x 2 x 2. Thus, the LCM of 6 and 8 is 3 x 2 x 2 x 2 = 24. Of all the answer choices, only 12 is a factor of 24, so n is divisible by 12.

Answer: B
_________________

Scott Woodbury-Stewart Founder and CEO

GMAT Quant Self-Study Course 500+ lessons 3000+ practice problems 800+ HD solutions

We’ve given one of our favorite features a boost! You can now manage your profile photo, or avatar , right on WordPress.com. This avatar, powered by a service...

Sometimes it’s the extra touches that make all the difference; on your website, that’s the photos and video that give your content life. You asked for streamlined access...

A lot has been written recently about the big five technology giants (Microsoft, Google, Amazon, Apple, and Facebook) that dominate the technology sector. There are fears about the...

Post today is short and sweet for my MBA batchmates! We survived Foundations term, and tomorrow's the start of our Term 1! I'm sharing my pre-MBA notes...