A boat takes half time in moving a certain distance downstream than upstream. The ratio of the speed of the boat in still water and that of the stream is?

3 : 1

ATQ, Speed is inversely proportional to Time.

(D.S)  Downstream speed = 2x

(U.S) Upstream speed = x

Boat : Stream = \(\frac{D.S + U.S}{2}\) : \(\frac{D.S - U.S}{2}\)

                       = \(\frac{2x + x}{2}\) :  \(\frac{2x - x}{2}\)

                       = \(\frac{3x}{2}\) : \(\frac{x}{2}\) = 3 : 1