The customer service center in a large New York department store has determined that the amount of time spent with a customer about a complaint is normally distributed, with a mean of 9.3 minutes and a standard deviation of 2.5 minutes. What is the probability that for a randomly chosen customer with a complaint, the amount of time spent resolving the complaint will be:
(a) Less than 10 minutes?
(b) Longer than 5 minutes?
(c) Between 8 and 15 minutes?