Binomial Math
posted by Bersy on .
A fair die is rolled four times. Calculate the probability of obtaining exactly two 5s. (Round your answer to four decimal places.)

prob of getting a 5 = 4/36 = 1/9
prob not a 5 = 8/9
prob getting a 5 twice in 4 rolls
= C(4,2) (1/9)^2 (8/9)^2 = 6 (1/81)(64.81) = 128/2187 = appr .0585 
A fair die is cast four times. Calculate the probability of obtaining at least two 6's. Round to the nearest tenth of a percent.

Nice answer you idiot.