Speed and other rates
Objective. Use rate as one quantity measured per unit of another.
- 1. Learn
- 2. Worked example
- 3. Practice
- 4. Feedback
- 5. Continue
Learn: the key idea
A rate compares two different quantities measured in different units, such as speed, which measures distance travelled per unit of time. The formula speed = distance ÷ time lets you calculate speed when distance and time are known, and rearranging it gives distance = speed × time or time = distance ÷ speed. For example, travelling 150 km in 3 hours gives a speed of 150÷3=50 km/h. Other rates work the same way, such as flow rate in litres per minute or pay rate in pounds per hour, always dividing one quantity by another to find 'per unit'.
Worked example
A cyclist travels 90 km at a steady speed in 2.5 hours. Find the cyclist's average speed as a rate in km/h.
- 1Identify the formula for speed: distance ÷ time.
- 2Substitute the values: 90÷2.5.
- 3Calculate the division: 90÷2.5=36.
- 4State the rate with correct units.
Answer: 36 km/h
Concept mastery
Based on your past attempts at this lesson — the question types to practise again come first.
Complete a practice set to see your concept breakdown here.
Practice
Practice happens on its own screen, one question at a time. Answers stay hidden until you submit yours, and you can stop and pick up at the same question later.
Start practisingCommon mistake. Pupils sometimes divide time by distance instead of distance by time when finding speed, giving an answer far smaller than expected. Always check which quantity the rate is measured 'per' before dividing.
Your progress
Tick each step as you finish it. Your exact reading position is saved automatically, so Continue drops you back on the same line.
0 of 5 steps complete
Your place saves automatically as you read.