Chapter 21, Problem 25P

A transportation engineering study requires that you determine the number of cars that pass through an intersection travelingduring morning rush hour. You stand at the side of the road andcount the number of cars that pass every 4 minutes at several timesas tabulated below. Use the best numerical method to determine

(a) The total number of cars that pass between 7:30 and 9:15, and

(b) The rate of cars going through the intersection per minute.(Hint: Becareful with units.)

Time (hr)	7:30	7:45	8:00	8:15	8:45	9:15
Rate (cars per 4 min)	18	24	14	24	21	9