Formulae for Streams and Boats

1. Downstream/Upstream:
   In water, the direction along the stream is called downstream. And, the direction against the stream is called upstream.
2. If the speed of a boat in still water is u km/hr and the speed of the stream is v km/hr, then:
   Speed downstream = (u + v) km/hr.

   Speed upstream = (u - v) km/hr.
3. If the speed downstream is a km/hr and the speed upstream is b km/hr, then:

   Speed in still water =	1	(a + b) km/hr.
   	2

   Rate of stream =	1	(a - b) km/hr.
   	2