A small gasoline station next to an interstate highway is open for 24 hours per day and has one pump and room for two cars, including the one that is using the pump. The mean arrival rate of cars is 8/hour and the mean service time at the pump is 6 minutes. The expected profit received from each car is $10. For an extra $120 per day, the owner of the station can increase the capacity for waiting cars by one. Is the additional capacity worth its cost?