Speed, Distance and Time
Speed, distance and time are linked by one formula: speed = distance ÷ time. So a car going 100 miles in 2 hours travels at 50 mph. Rearrange it to get the other two: distance = speed × time and time = distance ÷ speed.
Video Lesson
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Flashcards
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%20Finding%20Distance.webp)
%20Finding%20Speed.webp)
%20Finding%20Time.webp)
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%20Practice%20-%20Finding%20Speed%20with%20Time%20in%20Minutes.webp)
The Speed Triangle
- Distance sits on top, with Speed and Time underneath.
- Distance = Speed × Time, Speed = Distance ÷ Time, Time = Distance ÷ Speed
- Keep your units matched, such as mph with miles and hours.
Finding Distance
- When you know the speed and the time, multiply them to get the distance.
- Distance = Speed × Time
- A cyclist at 8 mph for 2.5 h covers miles.
Finding Speed
- When you know the distance and the time, divide the distance by the time.
- Speed = Distance ÷ Time
- A car going in 4 h has speed .
Finding Time
- When you know the distance and the speed, divide the distance by the speed.
- Time = Distance ÷ Speed
- A jogger doing 15 miles at 6 mph takes min.
Speed with Mixed Time
- A time like 3 h 30 min must become decimal hours before you divide.
- 30 , so 3 h 30 .
- Then .
Speed with Minutes
- A time given only in minutes must be changed to hours first.
- Divide by 60: .
- Then 30 miles mph.
Practice Questions
Test your understanding
A cyclist travels at 10 miles per hour for 3 hours. How far does the cyclist travel?
Correct! 🎉 +10 pointsNot quite right
Use distance = speed × time.
So .
The cyclist travels 30 miles.
A car travels in 2 hours. What is its average speed?
Correct! 🎉 +10 pointsNot quite right
Use speed = distance ÷ time.
So .
The average speed is per hour.
A train travels at an average speed of per hour. How long does the journey take?
Correct! 🎉 +20 pointsNot quite right
Use time = distance ÷ speed.
So .
Since 0.5 of an hour is 30 minutes, this is 1 hour 30 minutes.
(A common slip is to read 1.5 hours as 1 hour 50 minutes, but half an hour is 30 minutes, not 50.)
A cyclist travels at 12 miles per hour for 1 hour and 30 minutes. How far does the cyclist travel?
Correct! 🎉 +20 pointsNot quite right
First convert the time. 1 hour and 30 minutes is 1.5 hours.
Use distance = speed × time. So .
The cyclist travels 18 miles.
A runner completes in 40 minutes. What is the runner's average speed in km per hour?
Correct! 🎉 +20 pointsNot quite right
First convert the time. 40 minutes is of an hour.
Use speed = distance ÷ time. So .
The average speed is per hour.
(A common mistake is to write 40 minutes as 0.4 hours, but , which is wrong.)
A car travels 100 miles in 2 hours, then a further 120 miles in the next 3 hours. What is the average speed for the whole journey?
Correct! 🎉 +30 pointsNot quite right
Average speed uses the totals, not each part separately.
Total distance is and total time is .
Use speed = distance ÷ time. So .
The average speed is 44 miles per hour.
(A common mistake is to average the two speeds, 50 and 40, to get 45, but that ignores the different times spent at each speed.)
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Interactive Activity
Tap a corner of the triangle and adjust the values to find speed, distance or time.
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Students Also Ask
The questions students bump into most on this topic
The speed distance time triangle gives three formulas. Distance equals speed times time. Speed equals distance divided by time. Time equals distance divided by speed. Cover the quantity you want to find, and the other two letters show whether to multiply or divide them.
Picture distance at the top, with speed and time side by side at the bottom. To use it, cover the letter you want to find. If the other two sit side by side, you multiply. If one sits above the other, you divide the top by the bottom.
The units must match each other. If the speed is in miles per hour, the distance must be in miles and the time must be in hours. If a value uses different units, convert it first. For example, change minutes into hours before you divide.
Divide the number of minutes by 60, because one hour has 60 minutes. For example, 45 minutes divided by 60 is 0.75 hours. If a time is given as 3 hours and 30 minutes, 30 minutes is half an hour, so the total is 3.5 hours.
Keep the whole number of hours first. Then multiply the decimal part by 60 to change it into minutes. For example, 2.5 hours becomes 2 hours plus 0.5 times 60, which is 30 minutes. So 2.5 hours is 2 hours and 30 minutes.