A motorcyclist drives from A to B with a uniform speed of 30 km/h and returns back with a speed of 20 km h–1. Find its average speed.
ScienceClass 9CBSEAnswered 27 Mar 2026
Answer
Let the distance from A to B is D kms. Distance for the entire journey is 2D kms.
The time taken to go from A to B is D/30 hr, and that of B to A is D/20 hr. So, the total time taken T is T = (D/30) + (D/20). By solving, we will get,
T = D/12 hrs.
Average speed = Total distance/Total time. Av.speed = 2D ÷ D/12
=> 2D x 12/D = 24 km/h.
Hence Average speed of the motorcycle is 24 km/h.
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