Distance and time from speed
Turn the speed formula around.
Raghav's bus
Raghav goes to a neighbouring city in a bus moving at 50 km/h. The journey takes 2 h.
How can we find how far the city is?
What this lesson covers
The idea
Rearranging the speed relation gives Total distance covered = Speed × Total time taken, and Total time taken = Total distance covered / Speed.
Raghav's bus
Raghav goes to a neighbouring city in a bus moving at 50 km/h. The journey takes 2 h.
How can we find how far the city is?
- Multiply the speed by the time
- Divide the speed by the time
- Add the speed and the time
Bus and train
Find the distance of the bus journey. Then find the time of the train journey.
Two new forms
From Speed = distance ÷ time we get two more: distance = speed × time, and time = distance ÷ speed.
Total distance covered = Speed × Total time taken, and Total time taken = Total distance covered ÷ Speed.
- To find | Use
- Distance | Speed × Time
- Time | Distance ÷ Speed
- Speed | Distance ÷ Time
Notes
Total distance covered = Speed × Total time taken, and Total time taken = Total distance covered ÷ Speed.
Check yourself
A bus moves at 60 km/h for 3 h. How far does it go?
Answer: 180 km
60 km/h × 3 h = 180 km.
A train goes at 90 km/h. How many hours does it take to cover 360 km?
Answer: 4 h
360 km ÷ 90 km/h = 4 h.
A car travels at 40 km/h. How far does it go in 2 h?
Answer: 80 km
40 km/h × 2 h = 80 km.
A cyclist covers 30 km at 10 km/h. How many hours does it take?
Answer: 3 h
30 km ÷ 10 km/h = 3 h.