Calculate the annual emissions in gigatonnes of CO2 from the US fleet of passenger vehicles. The fleet is 200 million vehicles, average mileage is 24 MPG, and average driving distance is 12,000 miles/vehicle/year. Assume STP, fuel density is 0.7 kg/L, complete stoichiometric combustion, and that gasoline is pure octane.

(b) Calculate the CO2 emissions in lb/mil for the average vehicle.