Question

A boy's moves a certain distance with a speed of 30 kilometre per hour on the return trip along with same route there is less traffic and he takes 40 kilometre to cover the same distance find average speed

Answer 1

Explanation:

since equal distances are covered at 30 kmph and 40 kmph.

we can apply the formula =2xy/(x+y)

Average speed= 2×40×30/(40+30)

= 34.28kmph

OR

Let the distance to one side = x

Total distance = 2x

Time taken for forward journey= x/30

Time taken for return journey = x/40

Total time = x/30+x/40

= 70x/1200

Average speed=Totaldistance/TotalTime

= 2x/(70x/1200)

= 34.28 km/h .