The figure below shows the distance of a car from a measuring position located on the edge of a straight road.
(a) What was the average velocity of the car from t = 0 to t = 20 seconds?
(b) What was the average velocity from t = 10 to t = 30 seconds?
(c) About how fast was the car traveling at t = 10 seconds? At t = 20? At t = 30?