A person travels along a straight road for half of the distance with a velocity 60km/h and the remaining half distance with a velocity  80km/h. Then the average velocity is given by………

Given that  s1=s2     s2=s2v1=60 km/hv2=80 km/h∴ Time taken to cover first half of the distance  t1=s2v1Time taken to cover second half of the distance  t2=s2v2Average velocity  v¯=Total displacementTotal time=s1+s2t1+t2=s2+s2s2v1+s2v2=2v1v2v1+v2=2×60×8060+80=120×814=68.57km/h