A car is moving on a straight road covers one third of the distance with a speed of 20 kn/hr and the rest with a speed of 60 km/hr. the average speed of the car is?
Let the total distance be 3x.
Time taken to cover one-third of the distance = x/20
Time taken to cover two-thirds of the distance = 2x/60 = x/30
Total time = x/20 + x/30 = 5x/60 = x/12
Average speed = (Total distance travelled)/(Total time taken) = (3x)/(x/12) = 36 km/hr