Living in the Environment 18th Edition by Tyler Miller,Scott Spoolman

Exercise 23

Under normal driving conditions an internal combustion engine in a car produces approximately 200 grams (0.2 kilograms, or 0.44 pounds) of CO 2 per kilometre driven. Assume that a city you are studying has 7 million cars and that each car is driven an average of 20,000 kilometers (12,400 miles) per year.
If 20% of the city's residents were to walk, bike, or take mass transit instead of driving their cars in the city, how many metric tons (and tons) of the annual emissions of CO 2 would be eliminated