Rick D's Auto is specializes in replacing starters on cars and is well known for the specialty service. Rick and his team of mechanics can replace on average 4 starters per hour. Customers arrive on average at a rate of three per hour. They are served on a first in first out basis and come from wide and populous area. You can say its almost infinite as well since Rick D's is the only service centre that specializes in replacing starters.

a)Calculate the number of cars or customers in the system on average

b) Calculate the average time each car is in the system

c) Calculate the average number of cars waiting in line

d) Calculate the average wait time per car