Question
In how many ways can 12 students be put into groups of 3?
Answers
somebody
1 way,
4 groups of three
4 groups of three
Reiny
C(12,3) which says 12 choose 3
= 12!/(3!9!) = 220
Good calculators have that function build in
Look for <sub>n</sub>C<sub>r</sub>
enter 12
2ndF <sub>n</sub>C<sub>r</sub>
3
=
you should get 220
= 12!/(3!9!) = 220
Good calculators have that function build in
Look for <sub>n</sub>C<sub>r</sub>
enter 12
2ndF <sub>n</sub>C<sub>r</sub>
3
=
you should get 220
Reiny
misread the question.
I gave you "how many different groups of 3 can you choose from 12"
But you want 4 different groups of 3's, right?
that would be C(12,3) x C(9,3) x C(6,3) x C(3,3)
= 220 x 84 x 20 x 1
= 369600
I gave you "how many different groups of 3 can you choose from 12"
But you want 4 different groups of 3's, right?
that would be C(12,3) x C(9,3) x C(6,3) x C(3,3)
= 220 x 84 x 20 x 1
= 369600