Walking to school: You walk from home due east to school to get a book, and then you walk backwest to visit a friend. Figure 1.43 below shows your distance D, in yards, east of home as a function of...

Walking to school: You walk from home due east to school to get a book, and then you walk backwest to visit a friend. Figure 1.43 below shows your distance D, in yards, east of home as a function of the time t, in minutes, since you left home.

 a. How far away is school?

b. At what time do you reach school?

c. At what time(s) are you a distance of 900 yards from home?

d. Compute the average rate of change in D over the intervals from t = 0 to t = 3, from t = 3 to t = 6, and from t = 6 to t = 9.

e. What does your answer to part d tell you about how fast you are walking to school? How is this related to the shape of the graph over the interval from t = 0 to t = 9? ➞

 f. At what time are you walking back west the fastest?