Question

Erik drives 19.2 miles in 16 minutes.

He passes a sign which gives the speed limit as 65 mph.
By how much, in mph, did Erik's average speed exceed the speed limit?​

Answer 1

Erik's average speed exceeds the speed limit by 6.91 miles per hour.

Explanation:

Let suppose that Erik travels at constant speed. Hence, the speed (
`v`), measured in miles per hour, is determined by following equation of motion:

`v = (s)/(t)` (1)

Where:

`s` - Distance, measured in miles.

`t` - Time, measured in hours.

Please notice that a hour equals 60 minutes. If we know that
`s = 19.2\,mi` and
`t = 0.267\,h`, then the speed of Erik is:

`v = (19.2\,mi)/(0.267\,h)`

`v = 71.910\,(mi)/(h)`

Which is 6.91 miles per hour above the speed limit.