Question

A boy covers a distance of 60 km at a speed of 15 km/h by his motorcycle. Then he covers a distance of 48 km at a speed of 12 km/h by his car. Find the average speed of boy
1. 11.5 km/h
2. 7.5 km/h
3. 9.5 km/h
4. 10.5 km/h
5. 13.5 km/h

Answer 1

Correct Answer - Option 5 : 13.5 km/h

Given:

Distance covered by motorcycle = 60 km

Speed of motorcycle = 15 km/h

Distance covered by car = 48 km

Speed of car = 12 km/h

Formula Used:

Average Speed = Total Distance/Total Time

Time = Distance/Speed     

Calculation:

Time taken by motorcycle = 60/15 = 4 hours

Time taken by car = 48/12 = 4 hours

Total distance = Distance covered by motorcycle + Distance covered by car

Total distance = 60 + 48 = 108 km

Total time = 4 + 4 = 8 hours

Average speed = 108/8 = 13.5 km/h

∴ The Average speed of the boy is 13.5 km/h.