Answer the following in brief:
A car covers 68 \(km\) in the first hour, 72 \(km\) in the second hour, and 53 \(km\) in the third hour. Is the motion uniform? Justify your answer. Find the average speed of the car.
a) Is the motion uniform?
b) The average speed of the car is \(=\) \(km/h\)
[Note: Enter the answer in two decimal values]