Probability based on binomial distribution.
Richard has just been given a ten-problem multiple choice test in his history class. Each problem has five answers only one of which is correct. Since Richard has not attended class recently, he does not know any of the answers. Assume that Richard guesses randomly on all ten problems.
a) Find the possibility that he will answer all 10 problems accurately.
b) Find the probability that he will answer 5 or more problems accurately.
c) Find the probability that he will answer none of the problems perfectly.
d) Find the probability that he will answer at least 3 problems right.