A standby system currently has two servers (current system). Arrivals are Poissonian, with  = 20 customers per hour. The duration of the service follows an exponential distribution with  = 15 clients/hour. Average time between arrivals (minutes), x _a= T _a= _____________. Average service duration time (minutes), x _s= T _s= _____________. Current system: Average number of clients in the system (trained + being served), LS = _____________________. Current system: Average time of a customer in the system (trained + being served, in minutes), WS = _____________________. A Benchmarking study indicates that the time Ws of the competition is 5 minutes. This value then becomes the target to be reached. Minimum number of servers that allows to reach the target Ws, smin = ___________ Average time of a client in the system (trained + being served, in minutes), for the number of smin servers (from the previous section), WS = _____________________. The operating cost per server, cs, has been estimated to be $100/server-hour, while the waiting cost for clients, cw, is $1,000/client-hour. Optimal number of servers (minimizes the total cost of the standby system), s* = _____________________. Costs per hour (two decimal places) for s*: Waiting cost ($/hour): ____________________. Operating cost ($/hour): ____________________.