Question

A motorcycle drives from a to b with uniform speed of 30 km/h and return back with as speed of 20km/h find its average

Answer 1

Let dist between a & b be x kms

a to b:
Dist = x km
Speed = 30 km/hr
Time = x/30 hrs

b to a:
Dist = x km
Speed = 20 km/hr
Time = x/20 km/hr

Total dist = 2x kms

Total Time = x/30 + x/20 = (2x+3x)/60 = 5x/60 = x/12

Avg speed = Tot Dist/ Tot Time = 2x/ (x/12) = 2*12 = 24 km/hr