Answer:
6 cars per hour
Explanation:
The rate can be expressed several ways. One of them is "cars per hour". To find that rate, divide cars by hours:
(24 cars)/(4 hours) = 6 cars/hour
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If 6 cars were washed in 60 minutes, another way to express the rate is ...
(60 minutes)/(6 cars) = 10 minutes/car
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When you ask "what is the rate?", you need to be specific as to the rate you're interested in. Different expressions of the rate are useful for different purposes.