I need help figuring out how to solve these problems, I am only allowed to use a Calc TI 84 so if possible could you show me how to use some of the functions if it requires it. Need all three answered and I will up vote, also I cannot use excel and need details on how to solve. Thanks

1- Customers enter the lobby of a bank at rate of one every 90 seconds. A teller on average spends 3 minutes per customers. Find and . The best approach is to find the rates per hour. So if every 90 seconds (1.5 minutes) we have one customer, then we get 60/1.5=40 customers per hour. So =40/ hour. Since a teller spends 3 minutes per customer, then she can serve 60/3=20 customers per hour. So =20. 2- The Houston 911 Emergency Center receives on average 2 calls per minute. The 911 operator spends an average of 2.5 minutes per call. Find and . The arrival rate of calls is 2 per minute, then average arrival rate per hour is 120 calls. Since it takes 2.5 minutes to handle a call, the service rate is 60/2.5=24 calls per hour. So =120,=24. 3 - A vending machine dispenses coffee at constant rate of 30 seconds per cup. Customers arrive at rate of two every 90 seconds. Find and . The arrival rate is (60/1.5)(2)=80 per hour. The service rate is 60/.5=120 cups per hour