The Ace Wrecking Company operates a large fleet of trucks. These trucks average one call for mechanical service every 4 hours. Trucks generate revenue for Ace at the rate of $20 per hour. Ace's ace mechanic Thumbs Swenson, cost the company $12 per hour in wages, finges and equipment. Thumbs was found to average 20 minutes on a truck without thelp from the truck driver (2hours per truck with the truck drivers help) Assuming M/M1:FCFS/8/8 model:
a. What is the probability of 0,1 or 2 trucks in need of repair at any one time?