A motorcyclist drives from A to B with a uniform speed of 30 km h-1 and returns back with a speed of 20 km h-1. Find its average speed.
Let AB = x, So t1 = x /30 and t2 = x/20
Total Time = t1 + t2 = 5x / 60 hr
Average speed for entire journey = Total distance / Total Time
2x /5x /60 = 24 km hr-1
