A committee of 5 people must be formed from a group consisting of 8 people. How many different ways can be we form this committee?
my answer is
8p5= 6720.
Wrong answer!
I dont know the right answer yet, please help me!
2007-10-08 15:51:09 · 3 answers · asked by solvia k 2 in Science & Mathematics ➔ Mathematics
8C5 = 8! / (5!)(3!) = 8 * 7 * 6 / 3 * 2 * 1
8 * 7 * 6 / 3 * 2 * 1 = 4 * 7 * 2 = 28 * 2
28 * 2 = 56
Order doesn't matter, so permutation is useless.
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I apologize for my mathematical error.
2007-10-08 15:56:20 · answer #1 · answered by UnknownD 6 · 0⤊ 0⤋
8 P 5 gives you permutations, where order matters. If Joe is president and Sam is vice-president, that's different from Sam as president, Joe as vice president.
you want combinations (COMmittee, COMbination): 8 C 5 = (8•7•6)/(1•2•3) = 56
I had trouble with this back when I was a beginner. Hang in there.
2007-10-08 15:57:13 · answer #2 · answered by Philo 7 · 0⤊ 0⤋
You're close! In this case, you'll want to "choose" five from eight.
8c5 = 8! / [ 5! * (8-5)! ] = 56
2007-10-08 15:56:38 · answer #3 · answered by Ben 3 · 0⤊ 0⤋