Answer:
option c is correct
180 cars can they wash in 15 hours
Explanation:
Unit rate defined as the rate are expressed as a quantity 1 such as 4 miles per hour or 5 meter per second.
As per the statement:
Some students washed 24 cars in 2 hours
Then by definition of unit rate.

We have to find how many cars can they wash in 15 hours
⇒

Substitute the given values we have;

Simplify:

Therefore, 180 cars can they wash in 15 hours