Aptitude :: Boats and Streams

  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.

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