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Stupid Committees

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Stupid Committees

by Carloblacksun » Thu Nov 20, 2008 1:07 pm
If there are 16 people to choose from, what is the ratio of the number of possible 7-person committees to the number of possible 8-person committees?

A) 7:8
B) 8:7
C) 7:9
D) 8:9
E) 9:8

I found this question on some material downloadable from this website...

ciao ciao!!
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by earth@work » Thu Nov 20, 2008 2:00 pm
IMO : (D) 8:9
16C7 :16C8 = 16C7/16C8 = 8/9
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by mals24 » Thu Nov 20, 2008 2:08 pm
Agree with earth@work Answer should be D

16C7 = 16!/(7!*9!) = 4*5*2*13*2*11

16C8 = 16!/(8!*8!) = 2*5*13*11*9

16C7/16C8 = 8/9.
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by Carloblacksun » Thu Nov 20, 2008 2:10 pm
it's right!!

I used the wrong formula...this is why!! thanks a lot!!
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by logitech » Thu Nov 20, 2008 2:11 pm
NCK = NC(N-K)

For example:

16C7 = 16C9

It can be useful!
LGTCH
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