The machine repair model may often be used to approximate thebehavior of a computer’s CPU (central processing unit). Supposethat 20 terminals (assumed to always be busy) feed the CPU. Afterthe CPU responds to a user, he or she takes an average of 80seconds before sending another request to the CPU (this is calledthe think time). The CPU takes an average of 2 seconds to respondto any request.
On the average, how long will a user have to wait before the CPUacts on his or her request? How will your answer change if thereare 30 terminals? 40 terminals?
Of course, you must make appropriate assumptions aboutexponentiality to answer this question
