How many ways are there to choose a committee of 3 people from a group of 9 people?

Question

jim_thompson5910 · Answer

Hint:

use the formula

n C r = (n!)/(r!*(n-r)!)

In this case,

n = 9
r = 3

anonymous · Answer

i have no clue what the ~!~ mean??

jim_thompson5910 · Answer

example

6! = 6*5*4*3*2*1

jim_thompson5910 · Answer

it's factorial notation and hopefully you've learned about it before

anonymous · Answer

i still dont understand... i have never learned about this

jim_thompson5910 · Answer

n C r = (n!)/(r!(n-r)!)


9 C 3 = (9!)/(3!*(9-3)!)


9 C 3 = (9!)/(3!*6!)


9 C 3 = (9*8*7*6!)/(3!*6!)


9 C 3 = (9*8*7)/(3!)


9 C 3 = (9*8*7)/(3*2*1)


9 C 3 = (504)/(6)


9 C 3 = 84


So there are 84 ways to form a committee


If this all looks foreign, then you must have missed part of the lesson.

jim_thompson5910 · Answer

My suggestion is that if you've never heard of factorials, then it would be best to start here http://www.purplemath.com/modules/factorial.htm and that hopefully will make more sense

anonymous · Answer

thankyou!

jim_thompson5910 · Answer

you're welcome