Boat & Stream
In a river or stream, the direction along the flow of the stream is called downstream, and against the stream is called upstream.
- Suppose the speed of a boat or person swimming in still water is X and the speed of the river’s flow is Y.
- Speed of boat upstream = X – Y
- Speed of boat downstream = X + Y
- Suppose the speed of the boat downstream is A and upstream is B, then
- Speed of boat in still water = (A+B)/2
- Speed of flow of river = (A-B)/2