Answer:
<h2>B. The amount of fuel used was lowest at speeds around 60km/h.</h2>Step-by-step explanation:
The decreasing part is from (20,13) to (60,6), which gives an average rate of
Then, we have an increasing part from (60,6) to (120,10), which gives an average rate of
Basically, at 60 km/h the fuel used was 6 liters per 100 kilometers. Notice that the other velocities make the car to use more liters per kilometers.
Therefore, the amount of fuel used was lowest at speeds around 60 km/h.