Question

Sriya with her family travelled from Bolpur to Suri by car at a speed of $40$ km/hr and returned to Bolpur at a speed of $50$ km/hr.The average speed for the whole journey is.

Answer 1

Let the total distance from Bolpur to suri be $d$

Then Average speed = Total distance/Total time =$\frac{2d}{\frac{d}{40}+\frac{d}{50}}$

$=\frac{2d}{\frac{50d+40d}{2000}}$

$=\frac{4000d}{90d}$

$=\frac{400}{9}$ Km/Hr