A traveller covers a certain distance at $40$ km/h and returns over the same distance at $10$ km/h. The average speed for the whole journey is:
Practice this question from Chapter Mock 8: Speed, Time and Distance, with options and an explanation.
Question
A traveller covers a certain distance at $40$ km/h and returns over the same distance at $10$ km/h. The average speed for the whole journey is:
Option A — Correct answer
16 km/h
Correct choice.
Option B
20 km/h
Option C
24 km/h
Option D
25 km/h
Explanation
For equal distances, average speed $=\frac{2ab}{a+b}=\frac{2\times40\times10}{40+10}=16$ km/h.