Question

the ans is 48. but how to solve

Answer 1

let the distance between A and B be x
now, time taken by bus to travel from A to B = x/40
and time taken by bus to return from B to A = x/60
total time taken = x/40 + x/60 = x/24
total distance covered = x+ x = 2x
now, av speed = total distance / total time
= 2x/x/24 = 48 m/s
hope this helps