(From Ross) Consider a single-server queueing model in which customers arrive according to a nonhomogeneous Poisson process. Upon arriving they either enter service if the server is free or else they join in the queue. Suppose, however, that each customer will only wait a random amount of time, having distribution F, in queue before leaving the system. Let G denote the service distribution . Define variables and events so as to analyze this model, and give the updating procedures. Suppose we are interested in estimating the average number of customers by time T, where a customer that departs before entering service is considered lost