In this activity, we are working out average speed but the questions may require a change in units.

What does that mean?

Well, let's recap working out speed first!

__Recap__

Speed is a measure of **distance **in relation to **time.**

For example, a common one is the speed of a car. It is measured in mph or miles per hour or km/h kilometres per hour.

__Example__

What is the average speed of a car which travels 80 miles in 2 hours?

__Answer__

If the car travels 80 miles in 2 hours, we want to know how far it has travelled in 1 hour for the average speed.

80 ÷ 2 = 40 miles in 1 hour

Therefore, the **average speed is 40 mph.**

Let's say that instead of giving us the distance in hours it was given in **minutes!**

__Example__

Calculate the average speed a a car which travels 25 miles in 30 mins.

**Answer**

In the previous question, we were given 2 hours, so we divided the distance by 2.

This time, the car covers 25 miles in 30 mins so to get this to 1 hour we have to **multiply by 2 **(because there are 2 x 30 mins in 1 hour).

25 miles x 2 = 50 miles in 1 hour

**Average speed = 50 mph**

Let's have a go at some questions!