The graph show a distance travelled by four cars (A, B, C& D) over a period of time . Which car travelled at a greatest speed? *

Answer:
Car A traveled with the greatest speed.
Explanation:
We know that the steepness of the slope of the line on the distance-time graph represents speed.
Important Tip:
For example, at t = 5 seconds, the A car has covered more than 80 meters while all the other cars have covered less than 80 meters during the same period.
IIn fact, during the entire journey, it is clear that from the graph that the slope of the line of A car is more vertical — steep — than the slopes of cars B, C, and D.
Therefore, car A traveled with the greatest speed.