Need all parts answered:

 

9. Clay runs a small hotdog stand in downtown Chapel Hill. Clay can serve about 30 customers an hour. During lunchtime, customers randomly arrive at a rate of 20 per hour. a. (*) What percentage of the time is Clay busy? b. (*) On average, how many customers are waiting to be served? How many are in the system (i.e., waiting and being served)? c. (*) On average, how long will a customer wait to be served? How long will a customer be in the system?