Exercise :: Boats and Streams  Important Formulas
 Boats and Streams  Important Formulas
 Boats and Streams  General Questions
 Boats and Streams  Data Sufficiency 1
 Boats and Streams  Data Sufficiency 2

Downstream/Upstream:
In water, the direction along the stream is called downstream. And, the direction against the stream is called upstream.

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.

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