A computer retail store has 13 personal computers in stock. A buyer wants to purchase 2 of them. Unknown to either the retail store or the buyer, 2 of the computers in stock have defective hard drives. Assume that the computers are selected at random. (a) In how many different ways can 2 computers be chosen from 13? answer: (b) What is the probability that exactly one of the computers will be defective? answer: (c) What is the probability that at least one of the computers selected is defective