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# Combination Problem Solving

Author Message
Manager
Joined: 20 Nov 2005
Posts: 54
Location: Indianapolis, IN
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12 Dec 2005, 08:34
This topic is locked. If you want to discuss this question please re-post it in the respective forum.

Can someone briefly explain to me how one calculates combinations?

For example 12C3? (this was from a question recently posted).
Thanks!
Current Student
Joined: 29 Jan 2005
Posts: 5221
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12 Dec 2005, 08:43
N!/K!(N-K)!

So 12C3---> 12!/3!(12-3)!--->12!/3!*9!--->12*11*10/3*2*1--->220

Let me know if you still need further clarification.
Director
Joined: 10 Oct 2005
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12 Dec 2005, 08:49
Can someone briefly explain to me how one calculates combinations?

For example 12C3? (this was from a question recently posted).
Thanks!
My way is
12C3=12*11*10/1*2*3
for example 15C4=15*14*13*12/1*2*3*4
By the way 6C4=2C6 check yourself it will save sopme time and on real test time is really matters
N!/K!(N-K)! It is the same formula just a liitle bit simplier I think!Unfortunately don't remember the theory))But it works
Hope u find it useful!
Re: Combination Problem Solving   [#permalink] 12 Dec 2005, 08:49
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