1. the amount oftime, in minutes that a person must wait for a bus is uniformly dsitributed between 0 and 15 minutes, inclusive. what is the probability that a person waits fewer than 12.5 minutes?

2. A manager of a fast food restaurant observes that an average of 9 customer is served by a waiter in a on-hour time period. assuming that the service time has an exponential distribution, what is the probability that a customer shall be free within 12 minutes?

3. for a certain type of computer, the length of time between charges of the battery is normally distributed with a mean of 50 hours and standard deviation of 15 hours. John owns one of these computers and wants to know the probability that the length of time will be between 50 and 70 hours.