A car covers half the distance at a speed of 50 km/h and the other half at 40 km/h.
Fined the average speed of the car. (44.44 km/h).

Explanation

Let the total distance = x km.
First half is covered with a speed of 50 km/h.
`therefore` Time taken to cover first half of the distance `(t_(1))=(x/2)/50=x/100km`
Second half is covered with a speed of 40 km/h.
`therefore` Time taken to cover second half of the distance `(t_(2))=(x/2)/40=x/80km`
Total time = `t_(1)+t_(2)=x/100+x/80=(9x)/400`
Average speed of the car = `("Total distance")/"Time"=x/((9x)/(400))=400/9=44.44km//h`