Question

Suppose a man covers a certain distance at x km/hr and an equal distance at y km/hr. Then, the average speed during the whole journey is

Answer 1

Answer:

2020 When the distance covered remains same and the speeds vary : When a man covers a certain distance with a speed of x km/h and another equal distance at the rate of y km/h. then for the whole journey, the average speed is given by Average speed =2xy/(x+y) km/h.

Answer 2

let equal distance covered be d

time taken to cover distance d at x kmph = d/x

time taken to cover distance d at y kmph = d/y

average speed = (total distance)/(total time taken)

= 2d/(d/x + d/y)

= 2d/d{(x + y)/xy}

= 2xy/(x + y)