McBurger's fast-food restaurant has a drive-through window with a single server who takes orders from an intercom and also is the cashier. The window operator is assisted by other employees who prepare the orders. Customers arrive at the ordering station prior to the drive through window every 4.5 minutes (Poisson distributed), and the service time is 2.8 minutes (exponentially distributed). Determine the average length of the waiting line and the waiting time. Discuss the quality of the service.

Please plug in each formula in Excel spreadsheet.

Arrival rate () =
Service rate () =
Probability of NO customers in the system (P0) =
Propability of 3 customers in the system (P3) =
Average number of customers in the system (L) =
Average number of customers in the queue (Lq) =
Average time customer spends in the total queue system (waiting and served) (W) =
Average waiting time in the queue (Wq) =
Probabilty a server will be busy and customer must wait: Utilization factor (U) =