Question

a car travels A certain distance with a speed of 50 km per hour and returns with a speed of 40 km per hour calculate the average speed for the whole journey

Answer 1

Hello Mate!

Distance = d
Time = t1 and t2
Speed = 50 km/h amd 40 km/h respectively

As speed = distance / time
50 = d / t1
t1 = d / 50

40 = d / t2
t2 = d / 40

Now,

Average Speed = Total Distance / Total Time
= ( d + d ) / ( t1 + t2 )
= 2d / ( d /50 + d / 40 )
= 2d / ( 4d + 5d ) / 200
= 2d × 200 / 9d
= 44.44 km/h

Hope it helps☺!✌

Answer 2

I think it will help you