A motorboat going downstream overcame a raft at a point A; t = 60 minutes later, it turned back and after some time passed the raft at a distance l = 6.0 km from the point A. Find the flow velocity assuming the duty of the engine to be constant.
A boat can travel 10km/hr in still water. But upstream it tates 5 times of that time to cover the same distance. What time will the boat take to cover 180 km downstream ?