Example 1
A car travels 120 km at 40 km/h. How many hours does the trip take?
- Time = distance ÷ speed
- = 120 ÷ 40
- = 3 hours
Answer: 3 hours
Speed, Time and Distance Questions
Speed, time and distance with worked examples: time from distance and speed, and average speed over equal distances, plus free practice questions.
Practise speed, time and distance
How to solve speed, time and distance questions
Time from distance and speed
Time = distance ÷ speed. Keep the units matching: km and km/h give hours.
Average speed over equal distances
For two equal distances at speeds a and b, average speed = 2ab ÷ (a + b). It is less than the simple mean of the two speeds.
Worked examples
Example 2
A car drives to a town at 30 km/h and returns along the same road at 60 km/h. What is its average speed for the whole trip in km/h?
- For equal distances, average speed = 2ab ÷ (a + b)
- = 2 × 30 × 60 ÷ (30 + 60) = 3600 ÷ 90
- = 40 km/h
Answer: 40 km/h
Example 3
A bus covers 150 km at a steady 50 km/h. How long, in hours, does it take?
- Time = distance ÷ speed
- = 150 ÷ 50
- = 3 hours
Answer: 3 hours