BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

Stupid Committees

Expert replies
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!!
Join the discussion
Source: — Problem Solving |

by earth@work » Thu Nov 20, 2008 2:00 pm
IMO : (D) 8:9
16C7 :16C8 = 16C7/16C8 = 8/9
Join the discussion

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.
Join the discussion

by Carloblacksun » Thu Nov 20, 2008 2:10 pm
it's right!!

I used the wrong formula...this is why!! thanks a lot!!
Join the discussion

by logitech » Thu Nov 20, 2008 2:11 pm
NCK = NC(N-K)

For example:

16C7 = 16C9

It can be useful!
LGTCH
---------------------
"DON'T LET ANYONE STEAL YOUR DREAM!"
Join the discussion