Question

A car moving on a straight raid covers one-third of the total distance with 20 km/h and the remaining distance with 60 km/h. what is the average speed of the car?

Answer 1

Hell Mate!

Let the total distance be d,

One third of it = d / 3

Speed = Distance / Time

20 km/h = d / 3 / t1
t1 = d / ( 3 × 20 )
t1 = d / 60

Remaining distance = 2d / 3

60 km/h = 2d/3 / t2
t2 = 2d / 180

Average Speed = Total Distance / Total Time
= d / ( t1 + t2 )
= d / ( d / 60 + 2d / 180 )
= d / ( 3d + 2d ) / 180
= ( d / 5d )× 180
= 36 km / h

Hope it helps☺!