Here Some Basic Formulas/Rules Are given below :-
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
y km /hr, then, :
Speed downstream = (u + y) km/ hr
Speed upstream = (u - y) km/hr.
If the speed downstream is a km/hr and the speed upstream is b km /hr, then :
Speed in still water = 1/2 (a + b) km/hr
Rate of stream = 1/2 (a - b) km/hr