Answer:
The semi-trailer truck has the fastest average speed
Explanation:
Let's recall that the formula of the average speed is:
Average speed = Distance/Speed
Now, we can calculate the average speed for each class of vehicle, as follows:
Flatbed truck average speed = 144/5 = 28.8 miles per hour
Semi-trailer truck average speed = 327/4 = 81.75 miles per hour
Tanker truck average speed = 589/15 = 39.27 miles per hour
Which truck has the fastest average speed?
The semi-trailer truck has the fastest average speed