Question

A motor boat going downstream overcomes a float at a point A. 60 minutes later it turns and after some time passes the float at a distance of 12 km from the point A. The velocity of the stream is (assuming constant velocity for the boat in still water )
(1) 6 km/h
(2) 3 km/h
(3) 4 km/h
(4) 2 km/h

Answer 1

Yes and is 6km/hr

Let the speed of the motorboat beuand speed of stream bev.

Distance moved by the boat in 1 hour = (u+v)