Question

A body covers one third of its journey with speed u next third with speed v and the last one third with speed w .calculate the average speed of the entire journey

Answer 1

Explanation:

Average speed =

total distance /total time

we know that speed = distance/time

u = x/3t

t1 = x/3u........(1)

similarly

t2 = x/3v........(2)

also

t3 = x/3w.......(3)

Average speed =

total distance /total time

$\frac{x}{ \frac{x}{3u} + \frac{x}{3v} + \frac{x}{3w} } \\ 3u + 3v + 3w \\ 3(u + v + w)$