Exercise 9 Page 375

Practice makes perfect

a We are told that a traveler walks and takes a shuttle bus to get to a terminal of an airport. Let's consider the graph of the function y=D(x) that represents the traveler's distance in feet after x minutes.

We are asked to estimate and interpret D(2). Looking at the graph, we can see that D(2) is about 500 feet.

It means that the traveler has walked about 500 feet from their initial position after 2 minutes.

b In this part, we will find the solution of the equation D(x)=3500. From the graph, we can see that D(15)=3500.

x=15 is the solution to the equation. This means that the traveler has traveled 3500 feet in 15 minutes. Additionally, since this is the final point on the graph, it represents the terminal of the airport. Therefore, it took the traveler 15 minutes to get to the airport.

c Now we need to find how long the traveler waits for the shuttle bus. The waiting time should be the section of the graph where y has no change, since the traveler stays in one place.

We can see that the waiting time is from minute 4 to minute 12. Therefore, the traveler waits for the shuttle bus 12-4=8 minutes.

d We have found that the traveler waited for the shuttle bus until minute 12. It means that the graph section after minute 12 to the point where the increase rate of the graph changes represents the time the traveler rides on the bus.

We can see that the traveler rides on the bus until minute 13, which means that the traveler rides 3000-1000=2000 feet on the shuttle bus.

e In Part D, we found that the distance the traveler rides on the bus is 2000 feet. Additionally, from the graph we can see that the total distance traveled is 3500 feet.

Therefore, by subtracting the distance the traveler is on the bus from the total distance, we can find the distance the traveler walks before and after riding the shuttle bus. 3500- 2000=1500 The total distance that the traveler walks before and after riding the shuttle bus is 1500 feet.

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Exercises p.374-375

Exercise 9 Page 375

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