A shipping company operates a docking facility. On average, 3 ships arrive to unload their cargoes per hour. A team of workers unloads each ship. Each team costs $25 / hour. On average, each team can unload 6 ships in 5 hours. The firm pays an hourly charge of $10 per ship for the delay. Suppose the firm uses three teams of workers. What is the total hourly cost of the system? (Note: We add hourly cost of workers and hourly cost of the delay to obtain the total hourly cost of the system.)

a) About $75

b) About $110

c) About $135

d) About $95

e) No answer above is correct