suppose a queuing system has 2 servers, each with exponential service time with a mean of 3 hours, and the customer arrival times in this system are exponentially distributed with a mean of 4 hours. a customer has just arrived at 2pm. a) what is the probability that the next arrival will occur between 2 and 3 pm? b) suppose there are no additional customers 2 to 3pm, what is the probability that the next arrival will occur between 3 to 4pm? c) suppose one of the servers is under maintenance and the process changes to the following birth and death process with four states. construct the rate diagram for the birth and death process: state=(0,1,2,3). birth rate=(4,2,3,0). death rate=(0,1,6,2). d) given the inputs in part(c), develop the balance equations for this queuing system.