Boats And Streams Concept & Formula

Boats And Streams Concept=>

We can assume 2 objects in the stream

that is 

1)stationary object(which is run at stream's speed)

2)Moving object(which is run at stream's speed+its own speed)

In 2nd case Either object move in the direction of object or opposite direction of stream

A)In the Direction Of Stream(Called Downstream)

B)In the Opposite direction Of Stream( Called Upstream)

If x is the speed of a bot(in still water)

and y is the speed of the stream

Formula for

downstream a=x+y and

upstream     b=x-y

From Above two formula 

        x=(a+b)/2

        y=(a-b)/2

In Short,

Speed Of the boat in still water=x=(downstream speed+upstream speed)/2

And

Speed Of the Stream=y=(downstream speed-upstream speed)/2

I think It may be helpful to U....Thanks