Ok How many different ways can Ds and Rs be recorded if there are 5 slots?
I got 32 by doing 2*2*2*2*2. Is there another way to do this?
b)
3 must be Ds and 2 must be Rs... how many different ways can this be recorded?
I did 5!/3!2! = 10... is this correct?
2006-12-03 14:26:58 · 5 answers · asked by gg 4 in Science & Mathematics ➔ Mathematics
a) 32 is correct.
b) Again you are correct.
DDDRR
DDRDR
DDRRD
DRDDR
DRDRD
DRRDD
RDDDR
RDDRD
RDRDR
RRDDD
2006-12-03 14:39:53 · answer #1 · answered by Helmut 7 · 0⤊ 0⤋
i'm gonna guess and say 2^5
2006-12-03 14:30:48 · answer #2 · answered by Derek 4 · 0⤊ 0⤋
i assume order matters. otherwise your answers are wrong. but if order matters:
a) no problem
b) no problem
2006-12-03 14:31:37 · answer #3 · answered by socialistmath 2 · 0⤊ 0⤋
correct
by trial /error
2006-12-03 14:35:37 · answer #4 · answered by Anonymous · 0⤊ 0⤋
if its a combination......
nCr= n!/r! (n-r)!
n is the elements taken at r at a time.
if its a permutation......
nPr= n!/(n-r)!
2006-12-03 14:32:56 · answer #5 · answered by lucia c 1 · 0⤊ 0⤋