A small town with one hospital has 4 ambulances to supply ambulance service. Requests for ambulances during nonholiday weekends average 0.68 per hour and tend to be Poisson-distributed. Travel and assistance time averages 2.40 hours per call and follows an exponential distribution Use Table 1.

a. Find system utilization. (Round your answer to the nearest whole percent. Omit the "%" sign in your response.)

System utilization            %

b. Find the average number of customers waiting. (Round your answer to 3 decimal places.)

Average number of customers           

c. Find the average time customers wait for an ambulance. (Round your answer to 3 decimal places.)

Average time            hour

d. Find the probability that all ambulances will be busy when a call comes in. (Round intermediate calculations to 3 decimal places and final answer to 2 decimal places.)

Probability