A man takes twice as long to row a distance against the stream as to row the same distance in favour of stream. The ratio of speed of boat in still water and the steam is:
2:1
3:1
5:2
3:2
2:3
Upstream Downstream
Time 2 1
Speed 1 2 (Distance is same so time will be inversely proportional to speed)
The only option which is satisfying the ratio is 3: 1.
So, Option (B) is the answer.