Answer to Question #54699 in Statistics and Probability for alee

Question

A sales man knows that, on each visit to a customer, the probability of a sale is one fifth. Each day he makes three independent visits to customers.
Calculate the probability that, on a randomly selected day:
(a) all three visits result in sales. (5 marks)
(b) exactly two visits results in sales. (5 marks)
(c) less than two visits results in sales