During the campus Spring Fling, the bumper car amusement attraction has a problem of cars becoming disabled and in need of repair. Repair personnel can be hired at the rate of $20 person, if one person is hired, he or she works alone; two or three people work together on the same repair. One repairer can fix cars in an average time of 30 minutes. 2 repairers take 20 minutes and 3 repairers take 15 minutes. While these cars are down, lost income, is $40 per hour. Cars tend to break down at the rate of two per hour.