A boy traveled from the village to the post-office at the rate of 12.5 kmph and walked back at the rate of 2 kmph. If the whole journey took 5 hours 48 minutes, find the distance of the post-office from the village.  Choose the correct choice from the following choices.
A) 5 km
B) 7 km
C) 9 km
D) 10 km
E) 12 km
Explanation :   Solution: Average speed = 2xy/(x+y) km/hr   = (2*12.5*2)/(12.5+2) km/hr   = 50/14.5 km/hr.   Total distance = (50/14.5 * 29/5) km.   = 20 km.   Required distance = 20/2= 
<gadget id="calculator">20/2</gadget>
<output>10</output>
10 km.   Answer : 10 km
<result>D</result>
A boy traveled from the village to the post-office at the rate of 12.5 kmph and walked back at the rate of 2 kmph. If the whole journey took 5 hours 48 minutes, find the distance of the post-office from the village.