Answer:
Step-by-step explanation:
So, let's answer this question. If you want to observe and relate the number of cars per hour, then you have to divide the total number of cars (20 cars) by 4 hours totaling 5 cars per hour. On the other hand, if you want to compare and relate how long a car spends, it divides 4 hours by 20 cars and results in 1 car every 15 minutes.
So, it is five cars per hour or one car per fifteen minutes. But I think this question it's not biology, but what counts is knowledge.