Question

If a car covers 2/5th of the total distance with v₁ speed and 3/5th of the total distance with v₂ speed, then average speed of the car is

Answer 1

Let the Total Distance be x

Average Speed is Total Distance over Total Time

Time at v1 speed = Distance /Speed = 0.4x / v1

[(2/5=0.4)]

Time at v2 speed = Distance /Speed = 0.6x / v2

[(3/5=0.6)]

Total Time = x((0.4v2 + 0.6v1)/v1*v2)

Total Distance = x

Average Speed = (x/x)(v1*v2/(0.4v2+0.6v1)

Average Speed =(v1*v2)/(0.4v2+0.6v1) or (5v1v2)/(3v1+2v2)