Aconcrete service owns 3 mixer trucks to deliver concrete to work sites in a local area. for each order, a truck is loaded and weighed with mix at the single station for the order. then the truck makes the delivery and returns for the next load. assume that there is always an order for each truck. the delivery times are 15 minutes plus an exponential amount with mean 30 minutes and load/weigh times are 10 minutes. this is a variation on the single server queue with a fixed population of trucks. trucks are served at the loader and return to it as arrivals following their delivery. simulate this system by hand for 3 hours simulated time and report on the number of deliveries completed. the trucks begin empty, ready to be loaded.