Combinatorics : GMAT Quantitative Section
Check GMAT Club Decision Tracker for the Latest School Decision Releases

It is currently 19 Feb 2017, 09:00
GMAT Club Tests


GMAT Club Daily Prep

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.

for You

we will pick new questions that match your level based on your Timer History

Your Progress

every week, we’ll send you an estimated GMAT score based on your performance


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.


Request Expert Reply

Confirm Cancel

Events & Promotions

Events & Promotions in June
Open Detailed Calendar


  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message

Hide Tags

3 KUDOS received
Status: Applying for PhD
Affiliations: University of Peshawar
Joined: 21 Mar 2013
Posts: 4
Location: Pakistan
Concentration: Strategy, Marketing
Schools: HBS '15
GMAT Date: 07-31-2013
GPA: 3.4
WE: Education (Education)
Followers: 0

Kudos [?]: 9 [3] , given: 0

Combinatorics [#permalink]

Show Tags

New post 19 Aug 2013, 12:47
This post received
This post was
Here is a schematic presentation of how Combinatorics work.
Ask yourself two questions.

First, Does the order in which thing are done (or items are selected) matter in this question. If the answer is yes than its a Permutation problem. If the answer is no than it's a Combination problem.

Now when you have determined whether it's a combination or a permutation problem ask yourself the second question, is repeated selection allowed in this problem?
If "r" is the number of choices to be made and "n" is the total number of choices allowed than use the appropriate formula.

Permutation with repetition: n^r
Permutation without repetition: n!/(n-r)!
Combination with repetition: (n+r-1)/r!(n-r)!
Combination without repetition: n!/r!(n-r)!

Hope it helps, will try to add more detailed explanation with time. (Check the attachment and kindly give your feedback and suggestion).

Combinatorics.jpg [ 182.39 KiB | Viewed 1441 times ]

GMAT Club Legend
GMAT Club Legend
User avatar
Joined: 09 Sep 2013
Posts: 13869
Followers: 589

Kudos [?]: 167 [0], given: 0

Premium Member
Re: Combinatorics [#permalink]

Show Tags

New post 17 Jul 2015, 04:37
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.

GMAT Books | GMAT Club Tests | Best Prices on GMAT Courses | GMAT Mobile App | Math Resources | Verbal Resources

Re: Combinatorics   [#permalink] 17 Jul 2015, 04:37
    Similar topics Author Replies Last post
1 Experts publish their posts in the topic Combinatorics: Anagram ahmed1313 1 23 Jul 2015, 02:20
1 Experts publish their posts in the topic PS Combinatorics Cityboy 5 24 Apr 2013, 13:11
7 Experts publish their posts in the topic Combinatorics Summary fxsunny 7 29 Jan 2012, 22:28
Probability and Combinatorics gmatbull 3 20 Apr 2010, 09:02
200 Experts publish their posts in the topic Math: Combinatorics walker 38 27 Nov 2009, 10:05
Display posts from previous: Sort by


  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  

GMAT Club MBA Forum Home| About| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group and phpBB SEO

Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.