I forgot how to do this in class please explain to me how to solve them step by step. I need to know how to solve this on my own

5. How many minutes each hour is the mechanic idle (that is, not busy)? 6. What is the probability that you arrive at the shop for a new muffler and you do not have to wait to be serviced? 7. Suppose the manager of the auto repair show wants to reduce the amount of time a car spends in the system for a muffler installation by two-thirds. To accomplish this, what service rate will be required of the mechanic? Show your answers as cars per hour. Scenario: A small auto repair shop has one mechanic that is dedicated to the installation of new muffiers. Customers arrive for a new muffler on average every 30 minutes. The mechanic can install mufflers on average at the rate of 3 per hour. Assume this service can be modeled as a single-server model. 5. How many minutes each hour is the mechanic idle (that is, not busy)? 6. What is the probability that you arrive at the shop for a new muffler and you do not have to wait to be serviced? I-POP 7. Suppose the manager of the auto repair show wants to reduce the amount of time a car spends in the system for a muffler installation by two-thirds. To accomplish this, what service rate will be required of the mechanic? Show your answers as cars per hour