Question

a vehicle travels half the distance l with speed v1 and the other half with speed v2 then its average speed is - solution

Answer 1

Formula for average speed=total distance/total time

Let distance traveled =D

time taken in completing first half distance
=D/2(v1).
time taken to complete second half distance
=D/2v2.
so total time taken =D/2v2 + D/2v1
=D(v1+v2)/2v1v2.

so average speed=D/[D(v1+v2)/2v1v2]

=2v1v2/(v1+v2).