please solve A and B and show work

3. The Friendly Neighbor Grocery Store has a single check out stand with a full time cashier. Customers arrive randomly at the stand at a mean rate of 30Nhr. The service time distribution is exponential, with a mean of 1.5 minutes. The situation has resulted in occasional long lines and complaints from customers. Therefore, because there is no room for a second checkout stand, the manager is considering the alternative of hiring another person to help the cashier by bagging the groceries. This help would reduce the expected time required to process a customer to 1 minute, but the distribution still would be exponential. The manager would like to have the \% of time that there are in than 2 customers at the checkout stand down below 25%. She also would like to have no more than 5% of customers needing to wait at least 5 minutes before beginning service, or at least 7 minutes before finishing service. a. Use the formulas for the M/M/1 model to calculate L,W,W4,L2,P0,P1,P2 for the current mode of operation. What is the probability of having more than 2 customers at the check out stand? b. Repeat part (a) for the alternative being considered by the manager. c. Which approach should the manager use to satisfy her criteria as closely as possible