A man takes twice as long to row a distance against the stream as to row the same distance in favour of the stream. The ratio of the speed of the boat (in still water) and the stream is:
Choices
A) 1 : 2 B) 2 : 5 C) 6 ' ' 2 D) 3 : 1 E) 4 : 7

Rationale: explanation : let speed upstream = x hen , speed downstream = 2 x speed in still water = 2 x + x / 2 speed of the stream = 2 x - x / 2 speed in still water : speed of the stream = 3 x / 2 : x / 2 = 3 : 1 answer : d
Answer: D