Comcast Corporation is a global telecommunications company headquartered in Philadelphia, PA. Generally known for reliable service, the company periodically experiences unexpected service interruptions. When service interruptions do occur, Comcast customers who call the office receive a message providing an estimate of when service will be restored. Suppose that for a particular outage, Comcast customers are told that service will be restored in two hours. Assume that two hours is the mean time to do the repair and that the repair time has an exponential probability distribution.

a. What is the probability that the cable service will be repaired in one hour or less? 

b. What is the probability that the repair will take between one hour and two hours?

c. For a customer who calls the Comcast office at 1:00 p.m., what is the probability that the cable service will not be repaired by 5:00 p.m.?