Question 1094349
This is a binomial probability problem with the number of trials = 12 and the probability of "success" = 0.19
The probability of x successes in n tries is 
P(x) = C(n,x)p^x*(1-p)^(n-x), where p=probability of success and 
C(n,x) is the number of combinations of n things taken x at a time.
(a) P(x=3) = C(12,3)*0.19^3*0.81^9 = 0.2265