Question

A car cover first half of the journey with the speed of 20 kn/h and second half 30 km/h what is the average speed

Answer 1

let the distance be 2s

so s distance is covered in speed of 20km/h

hence time for s distance = s/20(* distance/speed)

similarly t2 = s/30

now average speed = total distance / total time

= 2s/s/30+s/20

24km/h