Response to the following problem:
Mark Trading Company employs two workers in its order processing department. Each worker processes orders according to an exponential distribution with a mean of 5 minutes. Customer arrivals follow a Poisson process with a mean of 18 customers per hour.
a. What is the probability that both workers are busy?
b. What is the probability that both workers are idle?
c. On the average, how long must an order wait before processing begins?
d. On the average, how many orders are being processed or are waiting to be processed?
e. What is the probability that exactly 3 customers will be in line waiting to be served at any given time?