Chapter 8.4A, Problem 18A

The following graph shows the relationship between the numbers of cars on a certain road and the time of day for times between $5:00\text{ A}\text{.M and 9:00 A}\text{.M}$.

a. What was the increase in the number of cars on the road between $6:30\text{ A}\text{.M}\text{. and 7:00 A}\text{.M}\text{.}$?

b. During which half hour was the increase in the number of cars the greatest?

c. What was the increase in the number of cars between $8:00\text{ A}\text{.M}\text{. and 8:30 A}\text{.M}\text{.}$?

d. During which half hour(s) did the numbers of cars decrease? By how much?

e. The graph for this problem is composed of segments rather than just points. Why do you think segments are used here instead of just points?