A mail order firm has one customer service representative. On average, one potential customer call CSD every four minute. The customer service representative requires on average 2 minutes to serve a customer. Both arrival and service time have a coefficient of 1.

(a) if the firm has to pay 5 cents for every minute of waiting for each customer, how much money the firm has to spend in a 8 hour period? Asssume customers can always enter the waiting line and will not hang up.

(b) The firm has an ambitious plan to cut customer waiting time by half, how much the service time has to change? (assume coefficient remains the same, if you can not solve the exact equation, do the best estimate you can)