Which of the following is the correctly abbreviated si unit describing the length of a rope

What is the average speed of a car that travels 40 mph for 1 hour and 60 mph in another hour?

Aplane flying horizontally at an altitude of 1 mile and a speed of of 500mih passes directly over a radar station. find the rate at which the distance from the plane to the station is increasing when it is 2mi away from the station.

Aforce of 100 newtons is used to move an object a distance of 15 meters with a power of 50 watts. find the work dine and the time it takes to do the work