A boat covers a certain distance downstream in 4 hours but takes 6 hours to return upstream to the
A boat covers a certain distance downstream in 4 hours but takes 6 hours to return upstream to the starting point. If the speed of the stream be 3 km/hr, find the speed of the boat in still water
15 km/hr
11 km/hr
13 km/hr
14 km/hr
12 km/hr