3. Suppose that a population of checkout counter service times in minutes is exponentially distributed with mean S = 4.0 min. (a) What is the probability that a single customer chosen at random has a service time of more than 5.0 minutes? (b) What is the chance that among 100 customers chosen at random, at least 25 customers will have service times of more than 5.0 minutes? Assume independence of service times. Include a continuity correction for this part