In general, the probability that a prospect will make a purchase after being contacted by a salesperson is p = 0.40. The salesperson selects three prospects randomly from a file and makes contact with them.
a) Construct a tree diagram to portray the sequence of three contacts, using S for sale and S' for no sale.
b) What is the probability that a salesperson will make at least two sales?
c) What is the probability that the salesperson will make at least one sale?