Speed distance time formula: speed = distance ÷ time
The speed distance time formula is speed = distance ÷ time.
What each letter means
- \(\text{distance}\) how far, e.g. in km or m
- \(\text{time}\) how long, in hours or seconds to match the speed unit
- \(\text{speed}\) the average speed, e.g. km/h or m/s
When to use it
For any journey at a steady (or average) speed. Rearranged: distance = speed × time and time = distance ÷ speed.
Worked example
A train travels 156 km in 2 hours 24 minutes. Find its average speed in km/h.
- \(2\text{ h }24\text{ min}=2+\tfrac{24}{60}=2.4\) hours
- \(\text{speed}=\dfrac{156}{2.4}\)
Answer: 65 km/h
Common mistake
Writing 2 hours 24 minutes as 2.24 hours. 24 minutes is 24/60 = 0.4 hours, so the time is 2.4 hours.
On your course
| Course | In the exam |
|---|---|
| Edexcel 4MA1 (Higher) | Not given: learn it |
| Cambridge 0580 | Not given: learn it |
From our own IGCSE Maths formula sheets, in our words. Official: Pearson's 4MA1 specification (PDF, Appendix 5) · Cambridge's 0580 syllabus (PDF).
Practise and revise
Questions
What is the speed distance time formula?
The speed distance time formula is speed = distance ÷ time. distance: how far, e.g. in km or m; time: how long, in hours or seconds to match the speed unit; speed: the average speed, e.g. km/h or m/s.
Is the speed, distance and time given in the exam?
Edexcel 4MA1 (Higher): not given: learn it. Cambridge 0580: not given: learn it. This comes from our own IGCSE Maths formula sheets; your teacher has the official booklet.
How do I find the average speed of a journey in two parts?
Divide the total distance by the total time. Do not average the two speeds.
Our own wording, examples and card, checked by IGCSE Math Revision. Not produced or endorsed by Pearson Edexcel.