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 N is the least positive integer that is a multiple of [#permalink]
20 Oct 2013, 20:09

ricardochavez wrote:

Well for the sake of the forum, and myself, could you post why exactly 3&5 were ignored?

Posted from my mobile device

To find the lowest common factor of a group of numbers, take the prime factorization of those numbers. For each prime number listed, take the most repeated occurrence of this number in any prime factorization. Then multiply them together.

15 = 3*5; 18 = 2*3^2; 3 occurs twice in 18 (3^2), it only appears one in 15. 40 = 2^3*5; 2 occurs thrice in 40, it only appears once in 18, and once in 50 50 = 2*5^2; 5 occurs twice in 50, it only appears once in 15.

So now that we see the highest power of each prime number that appears in these factorials we multiply them all together:

Re: If N is the least positive integer that is a multiple of [#permalink]
21 Oct 2013, 12:51

ricardochavez wrote:

Well for the sake of the forum, and myself, could you post why exactly 3&5 were ignored?

Posted from my mobile device

Least Common Multiple = the smallest multiple of two or more integers.

The LCM is the lowest product for all of the shared primes.

We ignore the 3 and 5 because we are looking to find the lowest common multiple.

LCM is not to be confused with the Greatest Common Factor- which is the common factor of ALL integers. They are easily mixed up!

Now to the problem:

Step 1. List the primes for each number

15 - 5,3 18 - 3,3,2 40 - 5,2,2,2 50 - 5,5,2

Step 2. Group common multiples - those that occur the most frequent

5,5(all but 18 have at least one 5 and you must be able to solve for each number given the primes. By having two 5's, we can still solve for 50) 3,3(18 and 15 both have 3, so we need two) 2,2,2 - we need at least three 2's to account for 40. Anything else would be redundant.

Step 3:Multiply together (2^3)(5^2)(3^2) = 1800

B is the only option that fits within the perimeters. _________________

Kudos if my post was helpful!

gmatclubot

Re: If N is the least positive integer that is a multiple of
[#permalink]
21 Oct 2013, 12:51

Low GPA MBA Acceptance Rate Analysis Many applicants worry about applying to business school if they have a low GPA. I analyzed the low GPA MBA acceptance rate at...

In out-of-the-way places of the heart, Where your thoughts never think to wander, This beginning has been quietly forming, Waiting until you were ready to emerge. For a long...