In order to encourage the use of carpooling, the city- of Beijing is considering putting carpool parking lots near major transportation arteries into downtown Beijing. Each parking lot allows commuters to meet in separate cars, park all but one, and proceed in one car to a joint destination. Studies estimate that an average of 200 cars will be parked at each lot on weekdays, with one-quarter of that number on weekends. The average commuting distance from the parking lots is 75 kilometres, and the marginal cost of driving an average car is 2 yuan per kilometre.
(a) If it is assumed that all the cars that are parked in the lot would othenvise have been driven to work, how much will be saved by this commuter parking lot per year? Assume an interest rate of 0.
(b) How could you find out how many would have been parked somewhere else?
(c) How could you calculate, per parking lot, the benefit to all drivers of having fewer cars on the road?