Question

evalute the expression 15 C 5

Answer 1

what's the formula for combinations?

Answer 2

ncr=n!/r!(n-r)!

Answer 3

good...let's use that

Answer 4

ok

Answer 5

15!/5!(15-5)

Answer 6

okay

Answer 7

almost...15!/5!(15-5)! <-- don't forget that last factorial

Answer 8

let me write it like this...it'll be clearer:

Answer 9

and now how would you get the answer

Answer 10

just by times it

Answer 11

well...what does ! mean?

Answer 12

! means factorial...what does that imply? like what does it stand for?

Answer 13

so the top is 36036000

Answer 14

only 2 zeors at the end

Answer 15

the bottoms 1200

Answer 16

i got it

Answer 17

good