A man take twice as long a to row a distance against the stream as to row the same distance in the direction of stream. What is the ratio of speed of man in still water to the speed of stream ?

3 : 1

The correct answer is option (2) : 3 : 1

Let the speed of man in still water be x km/hr and speed of stream be y km/hr.

Given time taken in upstream = 2 × time taken in downstream

$\frac{\text{time taken in upstream}}{\text{time taken in downstream}}=\frac{2}{1}$

i.e $\frac{2}{1}=\frac{x+y}{x-y}$

$2x-2y = x+ y$

$x= 3y$

$∴\frac{x}{y}=\frac{3}{1}$ i.e 3 : 1