A boy rides his bicycle 10 km at an average speed of 12 km/hr and travells 12 km at an average speed of 10 km/hr. His average speed for the entire trip is approximately :

Solution (By Examveda Team)

$$\eqalign{ & {\text{Average speed }} = \frac{{{\text{Total distance }}}}{{{\text{Total time}}}} \cr & {\text{Average speed }} = \frac{{{\text{10 + 12 }}}}{{\frac{{10}}{{12}} + \frac{{12}}{{10}}}} \cr & {\text{Average speed }} = 10.8{\text{ km/hr}} \cr} $$