The manager of a fast-food restaurant determines that the average time that her customers wait for service is 1.5 minutes. (a) find the probability that a customer has to wait more than 4 minutes. (round your answer to three decimal ) find the probability that a customer is served within the first minute. (round your answer to three decimal ) the manager wants to advertise that anybody who isn't served within a certain number of minutes gets a free hamburger. but she doesn't want to give away free hamburgers to more than 2% of her customers. what number of minutes should the advertisement use? (round your answer to the nearest minute.)