how many different comminities can be formed from 12 teachers, and 40 students, if the commitie consists 3 teachers and 4 students? In how many ways can the commitie of 7 members be selected?

Question

anonymous · Answer

find each seaprately (teachers and students) in the same way you have been, then multiply the two answers that you get.

anonymous · Answer

and then how does 7 come in?

anonymous · Answer

I keep getting a decimal for a number :/

anonymous · Answer

i can show u what I did

anonymous · Answer

out of 12 teachers you choose 3 = 12C3 and out of 40 students you choose 4 = 40C4

anonymous · Answer

Do those separately, then multiply the answers you get

anonymous · Answer

No decimals should show up

anonymous · Answer

for the 40 students is it 40*39*38*37?

anonymous · Answer

or is that when u do the 4?

anonymous · Answer

for Choosing when order doesn't matter, do 40*39*38*37 and then divide by 4*3*2*1
Similar for the teachers

anonymous · Answer

teachers is 12*11*10 divided by 3*2*1  --> notice that you get the same number of factors in the numerator as the denominator

anonymous · Answer

ok so now i got 91390 and then for the teachers 220

anonymous · Answer

multiply for a very large number