Calculate average speed, distance and time
Use total route distance and elapsed time to find average speed, rearrange for time or distance and convert compatible units across staged journeys.
Section 4.4 · Measures
Exam scope and assessment notes
Foundation and Higher share the seven published F:4.4A–G Measures rows. The Higher table says See Foundation Tier; there are no additional H4.4 rows. The chosen eight-lesson split covers instrument scales, time intervals, estimates, nearest-degree angle measurement, three-figure bearings, average speed, density and pressure. Eight lessons and thirty-two original worked/staged cases are StudyForA’s design, not a syllabus-prescribed count. Each structural source link requires the corresponding complete teaching record carrying that source ID, a worked explanation and all Guided, Independent and Transfer stages. F4.4F requires the complete speed lesson; broad F4.4G requires all three speed, density and pressure lessons, not a speed-only partial link. Source binding and substantive structure must belong to the same record; a separate untagged duplicate cannot supply missing evidence. These are structural links, not exhaustive subskill or specialist approval. Preserve the actual calibrated instrument ticks, pointer/meniscus positions, ruler endpoints, units and protractor alignment action. Read labelled scales rather than assuming CSS pixels are millimetres. Use only diagrams explicitly supplied as accurate for measurement; ordinary examination diagrams need not be to scale and must not be measured without instructions. Numerical reference readings, protractor openings and the measured bearing remain hidden before a calibrated learner attempt; revealing a reference is not proof of instrument operation. Keep ideal model values separate from approximate human readings and nearest-degree rounding; no universal automatic tolerance or measurement competence is established. Bearings start at the named origin and run clockwise from declared north, with parallel north assumptions stated and leading zeros retained. Distinguish reverse rays, interior route angles and forward heading changes; no magnetic or globe-navigation correction is inferred. Clock intervals retain am/pm, noon/midnight and day order. Average speed uses total route distance over the full named elapsed interval, including stated stops; displacement and instantaneous speed are different. Calculating time by division requires positive speed: at constant zero speed a positive distance is impossible, while zero distance alone does not determine elapsed time. Keep density mass/volume units compatible and volume positive; liquid displacement is final minus initial level. Combined volumes are added only under the stated no-void/no-volume-change assumption. The pressure formula is supplied in every pressure stage; do not infer that the density or average-speed formula is also supplied. Use a provided force in newtons, positive contact area, correct squared-area conversion and an explicitly limited average-pressure model. No real-world safety or route-feasibility certification follows. The source assessment context uses SI units and may require mathematical instruments. These lessons do not complete4.5 nearest-mm line drawing, formal shape/compass constructions or scale-drawing problems,5.2 transformations,4.8 bearing trigonometry,4.9/4.10 full mensuration or4.11 map/similarity work. No blanket formal-proof waiver is imported. Written practice is self-checked, not automatically marked; acknowledgements and attempts do not award marks or establish mastery. Specialist approval and formal assessment validation remain unestablished. Publisher navigation is separate evidence: literal F4.4D appears in Book2 Shape and Space6, map physical10/pages128–160, and Hub36 Bearings and Scale Drawings, co-tagged F4.5C/F4.11B; those co-tags confer no construction/map credit here. Literal F4.4G appears in Book1 Number5, map physical5/pages255–268, and Hub13 Compound Measures. A/B/C/E/F have no literal4.4 chapter or Hub tag in that map; do not invent one from nearby time or scale-drawing topics. Book1 public uncorrected-proof contents start Number5/Compound measures at256 and end its summary at269, conflicting with map255–268; preserve both references. Book2 chapter start128 and next start161 agree with its map range, but no explicit bearings contents heading locates every skill. Neither relevant chapter body is present in the public samples. Full final-book/Teaching Hub content and pagination alignment remain unverified; chapter links are not full-book or modular teaching credit. The current2026/2027 manual lists linear4MA1 F/H in November2026 and June2027; FR/HR are June2027 only, based on centre eligibility. Vietnam is on the regional-centre list; learner residence alone does not choose an option. The table points to page2 although the list is on physical/printed3. Modular4XMAF/4XMAH cash-ins and4WM units remain separate entries for international centres. This entry context does not create a2027 revision of the Issue2 specification.
Before you begin
- Convert minutes, hours, metres and kilometres.
- Calculate time intervals with stated day order.
- Rearrange a simple multiplicative relationship and distinguish total distance from displacement.
Work on paper. Try each question before revealing help, and explain why your method works.
Quick readiness check
How many hours are 45 minutes?
What you will learn
- Calculate average speed from total distance and the stated full elapsed time.
- Find speed, time and distance using compatible units in each direction.
- Combine journey stages and stops without averaging the listed speeds or confusing distance with displacement.
A vehicle travels 48 km in 40 min, stops for 10 min, then travels another 30 km in 30 min. Find its overall average speed for the whole journey in km/h and m/s. Explain which distances and times you include.
Read, draw and calculate before comparing. Every requested part and explanation needs your own attempt. The teal protractor and orange rays show your actual placements, including wrong ones. Comparisons do not award marks or establish practical instrument competence.
Coordinates use the original worksheet grid. The entire drawing and your tools rotate together; clockwise bearings retain their direction. Case or orientation changes clear all responses, placements and references. Named given points can be placed exactly; other drawing clicks use the nearest half-unit grid point and never snap to a solution.
Given panel 1
- Journey segments
Stage 1 - Duration: minutes part
- 40
- Distance (km)
- 48
Stage 2 - Duration: minutes part
- 10
- Distance (km)
- 0
- This segment is a stop
- Yes
Stage 3 - Duration: minutes part
- 30
- Distance (km)
- 30
- Elapsed time includes stops
- Yes
The board retains the last submitted valid placement. Editing a draft invalidates its submission without moving the last drawing; submit again before comparison.
Use the whole journey named in the question
Average speed is total distance travelled divided by total elapsed time for the stated interval. Distance adds along the route; returning towards the starting point does not subtract the distance already travelled. Displacement is a different quantity describing change of position. If the named journey includes a stop, that stop belongs in its elapsed time even though no distance is covered during it.
Average speed does not say that the vehicle moved at that speed every instant. Read the question to decide whether an interval covers the entire trip or only a specified moving section. Write a short distance-and-time record before substituting, especially when there are several stages or rests. Dividing by only the moving time answers a different question when the full journey includes stops.
Use all three forms with compatible units
Write s=d/t for speed, d=s×t for distance, and t=d/s for time, using positive elapsed times and the stated nonnegative route distances. Recovering time by dividing distance by speed requires positive speed. At constant zero speed, a positive distance is impossible; if the distance is also zero, that information alone does not determine the elapsed time. Rearrangement changes which quantity you can find; it does not change the need for compatible units. A speed in metres per second needs seconds for a distance in metres, while kilometres per hour needs hours for a distance in kilometres.
Convert minutes to hours by dividing by 60, not by 100. To convert km/h to m/s, multiply the kilometres by 1000 and divide the hours by 3600, giving division by 3.6 overall. Keep the unit calculation visible. For a known metres-per-second speed and a duration in minutes, first convert that duration to seconds. Multiplying the speed by the converted duration then produces a distance, not another speed.
Add stages before finding an average
Find each stage’s time when necessary, add all the relevant distances and elapsed times, then divide the totals. The arithmetic mean of two speeds is generally wrong because the stages may last different times. Even equal-distance stages can take different amounts of time, so their speeds must not be given equal time weights automatically.
For a deadline, subtract elapsed travel and any required future stop from the time still available, then calculate the speed needed for the remaining distance. A later constant-speed continuation is an explicit mathematical model, not a promise about roads, traffic or safety. An average required speed alone does not guarantee a feasible speed on every segment. These calculations do not establish velocity, acceleration or integration methods.
Sources for this lesson
Pause and explain
A vehicle travels 80 km at 40 km/h, then 60 km at 60 km/h without a stop. Which total-time calculation is needed?
Worked example
A vehicle travels 48 km in 40 min, stops for 10 min, then travels another 30 km in 30 min. Find its overall average speed for the whole journey in km/h and m/s. Explain which distances and times you include.
Show the worked solution
- Add route distances: 48+30=78 km. The stop contributes no distance but remains part of the whole-journey interval.
- Add elapsed times: 40+10+30=80 min. Convert to hours: 80÷60=4/3 h.
- Average speed is 78÷(4/3)=78×3/4=58.5 km/h. Dividing by 70 moving minutes instead would exclude the named stop and answer a different question.
- Convert to metres per second: 58.5÷3.6=16.25 m/s. Label this as an overall average, not a claim that the speed was constant throughout.
Answer Whole-journey average speed: 58.5 km/h=16.25 m/s, using 78 km over 80 min including the stop.
Try a topic test
Choose Easy, Normal or Difficult. Save your answers and open worked review after finishing.
Test this topic →From guided practice to a new situation
Write your answer and reasoning first. Use a hint only if you are stuck. The model solution is for self-checking; your written work is not automatically marked.
A cyclist covers 3.6 km in 15 min. Find the average speed in km/h and m/s. At that same constant speed, how long would 5 km take? In a separate fresh 6 min interval at the same constant speed, how far would the cyclist travel in metres and kilometres? Keep the two continuation questions separate.
Give me a hint
Use s=d/t first. Then use t=d/s for 5 km, and d=s×t after converting the fresh six minutes to seconds.
Compare my reasoning
- Convert 15 min to 15/60=1/4 h. The speed is 3.6÷(1/4)=14.4 km/h, equivalent to 14.4÷3.6=4 m/s.
- For 5 km at the same constant speed, use t=d/s with 5000 m: 5000÷4=1250 s. Divide by 60 to obtain 20 min with 50 s remaining, so the time is 20 min 50 s.
- For the separate fresh interval, 6 min=6×60=360 s. Use d=s×t: 4×360=1440 m.
- Convert 1440 m to 1.44 km. Both continuations assume that the recovered average speed is maintained constantly for the later stated interval; that is an explicit model assumption.
Speed: 14.4 km/h=4 m/s. Time for 5 km: 1250 s=20 min 50 s. Distance in a separate fresh 6 min: 1440 m=1.44 km.
Look for these in your work
- Use all three relationships to find the three different requested quantities.
- Convert 15 min to 1/4 h and the fresh 6 min to 360 s before substitution.
- Give correctly labelled speed, time and distance answers and state the constant-speed continuation assumption.
A journey has a 90 km stage at a constant 60 km/h followed by a 90 km stage at 90 km/h, with no stop. Independently calculate total time and overall average speed in km/h and m/s. A student suggests 75 km/h by averaging 60 and 90; explain whether that works.
Give me a hint
Equal distances do not mean equal travel times. Find both times before averaging the whole journey.
Compare my reasoning
- The first stage takes 90÷60=1.5 h. The second takes 90÷90=1 h. The total elapsed time is 2.5 h, with no stop to add.
- The total distance is 90+90=180 km. Overall average speed is 180÷2.5=72 km/h.
- Convert units: 72÷3.6=20 m/s. The result lies between the two stage speeds, as a sensible check.
- The suggested (60+90)÷2=75 km/h is wrong here because the slower speed lasts longer, 1.5 h rather than 1 h. Use distance over total time, not the unweighted mean of speeds.
Total time: 2.5 h. Overall average speed: 72 km/h=20 m/s. The suggested 75 km/h does not use the unequal stage times.
Look for these in your work
- Calculate both stage times and add them.
- Use 180 km over 2.5 h and convert the resulting speed to m/s.
- Explain why the simple 75 km/h average fails in this particular journey.
A 120 km delivery starts at 08:00 and must arrive by 10:40. After 60 km and 70 min, a 15 min stop is required. Find the average speed required over the whole allowed journey and the constant speed needed for the remaining 60 km after that stop. State the limits of interpreting the result as a real delivery plan.
Give me a hint
There are 160 minutes in the whole allowance. Deduct both the 70 minutes already used and the required stop before finding the remaining moving time.
Compare my reasoning
- From 08:00 to 10:40 there are 2h 40min=160 min=8/3 h. Over the whole 120 km journey, the required average is 120÷(8/3)=45 km/h.
- After 70 minutes, 60 km remain. Deduct the future 15 minute stop as well: 160−70−15=75 minutes of moving time remain.
- Convert 75 min to 1.25 h and use s=d/t: 60÷1.25=48 km/h for the stated constant-speed continuation.
- 45 km/h describes the whole allowed interval including the stop, while 48 km/h describes only the remaining moving section. These model numbers do not guarantee a feasible or safe speed on every road segment.
Whole-journey required average: 45 km/h. Remaining moving time: 75 min. Model constant speed after the stop: 48 km/h.
Look for these in your work
- Calculate the full 160 minute allowance and use compatible units.
- Remove the required future stop before calculating the remaining-stage speed.
- Distinguish the two averages and state the limit of the real-world interpretation.
Common mistakes
- Ignoring a stop included in the named interval or using net displacement instead of total distance.
- Treating minutes as decimal hundredths of an hour or mixing km/h with seconds without conversion.
- Averaging stage speeds without their times, or treating a model average as a real-world feasibility guarantee.
What can you explain now?
A walker travels 2 km out and 2 km back in one hour. Is the average speed zero because the finish is the start?
Compare with the explanation
No. The total distance is 4 km, so average speed is 4 km/h.
The displacement is zero, but distance adds along the route. Average speed uses the 4 km travelled and the one-hour elapsed time, not the change of position.
After trying it yourself, choose your next review. This is your self-assessment.
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Make it stick
Write s=d/t, d=s×t and t=d/s from memory. Explain what total distance and elapsed time mean when a route includes a stop or returns to its start, and recall the km/h-to-m/s conversion.
If you needed the solution, close it and solve the problem again from a blank page. A correct answer is stronger when you can explain the reason for each step.