Need a, b, c and d. Thanks!

If = 7.5 entities / hr and = 10 entities / hr

a. Calculate the minimum number of servers to reach steady state (Sm).

Given that the cost of operating each server is $ 30.00 per hour and the opportunity cost for the entity that is on hold is $ 10 per hour.

b. Calculate the expected cost of operating the system if you use the minimum number of servers calculated in part a.

c. Calculate the expected cost of operating the system if you use S = Sm + 1.

d. Did you reach the optimum or will it be necessary to continue the search?