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:

8C2*6C2*4C2*2C2 = 2520 ways 8 people will form 4 teams of 2 each
My guess is we need to divide this number by 4C2 (two teams from 4 possible teams can play a game of doubles) ...
Hence, 2520/4C2 = 2520/6 = 420

Thats the only explanation I can think of... I must admit initially I thought the answer was 2520 too...
_________________

If you pick one player, he has 7 possible partners.
We have six left, if we pick one, he has 5 possible partners.
We have four, if we pick one, he has 3 different possible partners,

If you pick one player, he has 7 possible partners. We have six left, if we pick one, he has 5 possible partners. We have four, if we pick one, he has 3 different possible partners,

Therefore 7*5*3=105

Its difficult for me to understand.

If you pick one player, he has 7 possible partners.

here, first player could be picked from pool of 8 people each having 7 remaining people as partner. All combinations seems 8*7 rather than just 7. Dont know what I am missing.

Order isnt imp and isnt that the reason why we have used combination instead of Permutation here??? why do we need to divide the outcome by 4! pls explain.....

There's two things going on here:
(1) ordering between members in a team.
(2) ordering between teams

In this question order is NOT relevant on both counts. Using combinations ensures ordering between members is excluded.
Dividing by 4! makes sure ordering between teams is also excluded.
I hope this helps

There's two things going on here: (1) ordering between members in a team. (2) ordering between teams

In this question order is NOT relevant on both counts. Using combinations ensures ordering between members is excluded. Dividing by 4! makes sure ordering between teams is also excluded. I hope this helps

thanks sadsack for clearing the confusion... its a great help indeed!

With that one, it's painfully obvious that I'm totally lost with permutations and combinations. Anybody got any suggestions? I've gone through the GMAT club course material, and a couple of other books too. Still my mind just refuses to think in the proper way!!!

Order isnt imp and isnt that the reason why we have used combination instead of Permutation here??? why do we need to divide the outcome by 4! pls explain.....

I had the same problem Tingle. This was my issue. thanks sadsack for the clear post.

anandsebastin> I too am completely dumbfounded when it comes to these thypes of problems, which is exactly why I keep posting them over and over again, scrutinizing the methodology. Have you checked out the book Veritas Project GMAT yet? I have heard that they really drill in this subject matter.