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:

Am not trashing MGMAT's guides...in fact, I'm a fan. But, I think the combinatorics section could've been written a bit more clearer, coz I remember being able to solve these problems using easier techniques in the past.

Am not trashing MGMAT's guides...in fact, I'm a fan. But, I think the combinatorics section could've been written a bit more clearer, coz I remember being able to solve these problems using easier techniques in the past.

Clear, Crisp & Concise formulas for the 4 categories of problems:

[n is the size of the pool, r is the # of objects we're selecting from the pool]

1) ORDER MATTERS = Y, REPETITIONS = allowed Formula: n raised to the power r

2) ORDER MATTERS = Y, REPETITIONS = not allowed (nPr) Formula: n! / (n-r)!

3) ORDER MATTERS = N, REPETITIONS = allowed Formula: (n+r-1)!/( (r!) (n-1)!)

4) ORDER MATTERS = N, REPETITIONS = not allowed (nCr) Formula: n! / ( (r!) (n-r)! )

Thought I'd share this for others struggling to remember what you learned years ago...

If you are hoping to solve all P&C questions using formulas, you will be disappointed. There are a ton of them. One word in the question changes and your formula becomes useless (though there is a new formula for it then). You need to understand some basic concepts of the topic. That will help you handle most of the questions.
_________________

Only the 3rd combination I am finding difficult to explore. Rest was nicely explained in the link, thanks.Karishma, you mention about basics, apart from MGMAT guides and forum discussions, would you have any references for those? Pls advice
_________________

"When the going gets tough, the tough gets going!"

Only the 3rd combination I am finding difficult to explore. Rest was nicely explained in the link, thanks.Karishma, you mention about basics, apart from MGMAT guides and forum discussions, would you have any references for those? Pls advice

Veritas has a book dedicated to Combinatorics and Probability. It is one of the most comprehensive sources for GMAT Combinatorics theory and practice questions.

Only the 3rd combination I am finding difficult to explore. Rest was nicely explained in the link, thanks.Karishma, you mention about basics, apart from MGMAT guides and forum discussions, would you have any references for those? Pls advice

Try Combinatorics chapter of Math Book to have an idea about the staff that is tested on the GMAT: math-combinatorics-87345.html

In addition, note that usually the GMAT combination/probability questions are fairly straightforward and as practice shows you won't encounter more than 2-3 questions from this field.

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.
_________________

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...