3. Consider an M/G/1 queueing system in which service is given as follows. Upon entry into service, a coin is tossed, which has probability p of giving Heads. If the result is Heads, the service time for that customer is 0 seconds. If Tails, his service time is drawn from an exponential distribution with parameter/) (same as the tossing Head probability). (20%) (a) Find the average service time (b) Find the variance of service time (c) Find the expected waiting time W. (d) Find the Laplace transform of the waiting time W'(s) s+ p