to solve the average number of cars owned by each teacher, multiply the number of cars to its corresponding probabilty and add them up.
ave = (0 * 0.03) + ( 1 * 0.13) + ( 2 * 0.70) + ( 3 * 0.10) + ( 4 * 0.04)ave = 0 + 0.13 + 1.40 + 0.30 + 0.16ave = 1.99 or about 2 cars is the average number of cars owned by each teacher