Correct Answer - Option 3 : 20 km/h
Given :
A man covers 40% distance at a speed of 20 km/h, 50% of the remaining at speed of 30 km/h and remaining distance with a speed of 15 km/h
Formula used :
Average speed = Total distance/Total time
Calculations:
Let the total distance be '100x' km
40% of the distance = 40x
50% of the remaining distance = 50% of 60x = 30x km
Remaining distance = 30x km
Total time = (40x/20) + (30x/30) + (30x/15)
⇒ 5x
Average speed = Total distance/Total time
⇒ 100x/5x
⇒ 20 km/h
∴ The average speed will be 20 km/h
