If a person travels three equal distances at speeds of 20 km/h, 30 km/h, and 10 km/h, then find the average speed of the whole journey.
Show answer & explanation
Correct answer: D
Explanation
The correct answer is Option 4 i.e. 16.36 km/h.
Let each distance = D km and Total distance = 3D km
Total time = D/20 + D/30 + D/10 = 11D/60 hours
Average speed = 3D/(11D/60) = 180/11 ≈ 16.36 km/h