A car is going 50 miles per hour a rate that describes this would have units of

b. Miles and hours

Step-by-step explanation:

If a rate were to be used to describe the speed that the car was going at, it would be MPH (miles per hour) which is a British and American unit used to describe the speed at which something is going. The car for instance is travelling at a speed of 50 MPH.

This composite unit is made up of 2 other units which are miles and hours.

relating to or denoting a system of numbers and arithmetic based on the number ten, tenth parts, and powers of ten.

it alot will look like this 4.4