Who this is for: Cambridge IGCSE Mathematics (0580/0607) students who want Speed, Distance and Time — the SDT formula, unit conversions and average-speed problems — to become a reliable source of marks instead of a topic they only half-remember.
What query it owns: how to understand and revise Speed, Distance and Time in Cambridge IGCSE Mathematics.
Why this is safe: this page owns the Speed, Distance and Time revision-guide angle, while Tutopiya’s Speed, Distance and Time subtopic page owns the learning resource and the free Speed, Distance and Time quiz owns the practice.

Speed, Distance and Time is one of the most applied subtopics in Cambridge IGCSE Mathematics (0580/0607). Journey problems, unit conversions and average-speed calculations appear regularly on both papers. If you know the SDT triangle and can convert between km/h and m/s, you pick up marks quickly. This guide explains exactly what the subtopic covers, how to handle the question types that actually appear, and where to practise each skill.

Key takeaways

• Speed = distance ÷ time — rearrange to find any missing quantity.
• Units must match: km with hours (km/h), metres with seconds (m/s).
• Convert km/h → m/s by ÷ 3.6; m/s → km/h by × 3.6.
• Average speed = total distance ÷ total time — not the average of two speeds.

What is Speed, Distance and Time in Cambridge IGCSE Maths?

Speed, Distance and Time is the study of how fast an object travels and how journey length relates to time taken. In Cambridge IGCSE Mathematics it covers the formula speed = distance ÷ time, converting between units (km/h and m/s, minutes and hours), and calculating average speed over multi-part journeys. Examiners test it with realistic travel scenarios.

You can read the full explanation, worked examples and notes on Tutopiya’s Speed, Distance and Time subtopic page before you attempt questions.

The core ideas you must master

These five ideas appear again and again. Learn what each one means and the exam phrasing that signals it.

Idea	What it means	How the exam uses it
Speed = d ÷ t	Rate of travel	”Work out her average speed”
Distance = s × t	Journey length	”How far does the car travel in 2.5 hours?”
Time = d ÷ s	Duration of journey	”Work out how long the journey takes”
km/h ↔ m/s	÷ 3.6 or × 3.6	”Convert 72 km/h to m/s”
Average speed	Total distance ÷ total time	”Find the average speed for the whole journey”

How to solve SDT problems — step by step

The most reliable method is to write the formula, check units, then substitute.

1. Identify what you need — speed, distance or time — and write the correct formula.
2. Convert units so they match. Example: 90 minutes = 1.5 hours before using km/h.
3. Substitute and calculate. Distance = 60 km/h × 2.5 h = 150 km.
4. For average speed, add all distances and all times separately: avg = total d ÷ total t.
5. Check the answer is sensible — a walking speed of 500 km/h is clearly wrong.

Once you have worked through a few, test yourself with the free Speed, Distance and Time quiz — it tells you fast whether the method has actually stuck.

Average speed vs speed conversion: which method applies?

Students lose marks by averaging two speeds or using the wrong conversion factor.

Problem type	Method	Common trap
Find speed	d ÷ t	Time left in minutes, speed in km/h
Convert km/h → m/s	÷ 3.6	Multiplying instead of dividing
Average speed (two legs)	(d₁ + d₂) ÷ (t₁ + t₂)	Averaging the two speeds directly
Find time	d ÷ s	Forgetting to convert hours to minutes

Speed, Distance and Time in past-paper wording: command words that matter

Most lost marks come from misreading the command word or using inconsistent units.

Command word / phrase	What the question wants	Typical stem
Work out the average speed	Total distance ÷ total time	”Work out her average speed for the whole journey.”
How far does … travel in	distance = speed × time	”How far does the train travel in 45 minutes at 80 km/h?”
Work out how long	time = distance ÷ speed	”Work out how long a 240 km journey takes at 60 km/h.”
Convert … to m/s	÷ 3.6 from km/h	”Convert 54 km/h to metres per second.”
Calculate / Work out	Numerical answer with method	”Calculate the speed in km/h.”
Show that	Prove a stated journey result	”Show that the journey takes 2.5 hours.”

Worked exam-style stems (how to answer the wording)

Practising the wording — not just the maths — is what full marks reward.

1. “A car travels 180 km in 2 hours 30 minutes. Work out its average speed in km/h.” Time = 2.5 h. Speed = 180 ÷ 2.5 = 72 km/h. Reward: time converted, correct division.
2. “Convert 90 km/h to m/s.” 90 ÷ 3.6 = 25 m/s. Reward: division by 3.6 shown or implied.
3. “A cyclist rides 12 km at 16 km/h, then 8 km at 20 km/h. Work out the average speed for the whole journey.” t₁ = 12/16 = 0.75 h; t₂ = 8/20 = 0.4 h. Total d = 20 km, total t = 1.15 h. Avg = 20 ÷ 1.15 = 17.4 km/h (3 s.f.). Reward: total distance and total time, not average of 16 and 20.

When you can recognise the wording instantly, work the full set on the Number topical past-paper questions and the Speed, Distance and Time quiz to lock the method in.

How Speed, Distance and Time connects to the rest of Number

SDT uses direct proportion from Ratios and Proportions. Unit conversion overlaps with Estimation and Rounding Numbers. Rate problems extend the same ideas in the Rate subtopic. When you are ready to mix topics, the Cambridge IGCSE Maths resource hub lets you move straight from a weak subtopic into the next.

Common mistakes students make

• Averaging two speeds instead of using total distance ÷ total time.
• Leaving time in minutes when speed is in km/h.
• Converting km/h to m/s by × 3.6 instead of ÷ 3.6.
• Forgetting to convert hours and minutes to decimal hours (2 h 15 min ≠ 2.15 h).

When you need more support

If SDT or unit-conversion questions keep tripping you up, work through the Ratios and Proportions quiz and the Number topical past-paper questions to pinpoint the exact gap, then get focused help from a Cambridge IGCSE Maths tutor to fix it quickly.

Frequently asked questions

Is Speed, Distance and Time hard in Cambridge IGCSE Maths? No — one formula drives everything. The challenge is unit conversion and not averaging speeds incorrectly.

What is the SDT formula? Speed = distance ÷ time. Rearrange: distance = speed × time; time = distance ÷ speed.

How do I convert km/h to m/s? Divide by 3.6. Example: 72 km/h = 72 ÷ 3.6 = 20 m/s.

How do I revise Speed, Distance and Time effectively? Read the subtopic notes, practise SDT and average-speed questions by hand, then take the Speed, Distance and Time quiz to check your method.

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