A boy rides his bicycle 10 km at an average speed of 12 km/hr and again travels 12 km at an average speed of 10 km/hr. His average speed for the entire trip is approximately?
Choose the correct choice from the following answers
A) 10.8 km/hr  B) 12.8 km/hr  C) 11.8 km/hr  D) 16.8 km/hr  E) 17.8 km/hr
A   10.8 km/hr   Total distance traveled = 10 + 12= 
<gadget id="calculator">10 + 12</gadget>
<output>22</output>
22 km /hr.   Total time taken= 10/12 + 12/10 = 61/30 hrs.   10.8 km/hrverage speed = 22 * 30/61 = 10.8 km/hr.
<result>A</result>
A boy rides his bicycle 10 km at an average speed of 12 km/hr and again travels 12 km at an average speed of 10 km/hr. His average speed for the entire trip is approximately?