A job shop consists of three machines and two repairmen. The amount of time a ma- chine works before breaking down is exponentially distributed with mean 10 hours. The amount of time it takes a single repairman to x a machine is exponentially distributed with mean 8 hours. Note that only a person repairs a broken machine. solve by markov chain
(a) What is the average number of machines not in use?
(b) What proportion of time are both repairmen busy?
(c) What proportion of time is a repairman busy?
(d) If a working machine provides the pro t of $ 18 per hour and the amount of $ 30 per hour should be given to a repairman, does the owner of a job shop keep only a single repairman?