Repairman finds that the time spent on his jobs have an exponential distribution with mean of 30 minutes.

A T.V. Repairman finds that the time spent on his jobs have an exponential distribution with mean

of 30 minutes. If he repairs sets in the order in which they come in, and if the arrival of sets is

approximately Poisson with an average rate of 10 per 8 hour day, what is repairmanís expected idle

time each day? How many jobs are ahead of the average set just brought in?