# Math Help - number of ways a switch can be set

1. ## number of ways a switch can be set

if 8 switches can set to position a or b and an equal amount of switches are set to a as to b. How many ways could this be done?
i though you could do this with $\frac{8!}{4!.4!}$ but i got the wrong answer.

D: i suck at probability

2. Originally Posted by renlok
i though you could do this with $\frac{8!}{4!.4!}$ but i got the wrong answer.
There are two possiblities for each of eight switches: $2^8.$

3. yeah but 4 switches have to be a and 4 have to be b

4. Originally Posted by renlok
yeah but 4 switches have to be a and 4 have to be b
Well then it is $\frac{8!}{(4!)^2}.$