Question 996195:  Distance covered from home to school at 3 km/hr and school to home at 4km/hr, time taken 21 minutes, find distance from home to school. 
 Answer by Alan3354(69443)      (Show Source): 
You can  put this solution on YOUR website! Distance covered from home to school at 3 km/hr and school to home at 4km/hr, time taken 21 minutes, find distance from home to school. 
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Avg RT speed = 2*3*4/(3+4) = 24/7 km/hr 
RT distance = (24/7)*(21/60) km 
= 1.2 km 
--> 0.6 km each way 
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