The graph below shows the relationship between the pages read in a 40-page book and the time spent reading the book.
What is the rate of change that represents this function?
60
A 1.4 pages per minute
B 2.5 minutes per page
C 0.4 pages per minute
D 2.5 pages per minute
55
50
45
40
Number of pages
35
30
25
20
15
10
5
20
24
8 12 16
Time (minutes)