a large call center has several thousand employees who use digital telephones. historical data shows that an average of 8 users need some help with their phones each hour. the company currently has one expert technician to handle these problems. the service time for taking care of user’s telephone problem is exponential with a mean of 6 minutes. the users cannot do anything productive while their phone is not working. a typical user’s time is valued at about $40 per hour and the expert technician gets paid about $30 per hour.