You roll a die 3 times.

(a) What is the probability of getting a total of two 5's from all three rolls of the die?

(b) What is the probability of getting a total ofat leasttwo 5's from all three rolls of the die?

So for (a), I think of it this way: P(5 5 5') where 5 is the probability of getting a 5 and 5' is the probability of not getting a 5. So:

P(5 5 5') = (1/6)*(1/6)*(5/6) = 5/216. So my answer for (a) would be 5/216.

Whats the correct way to think about (b)? Thanks,

Kim