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	Choose the correct choice from the following:
A) 1:2	B) 1:3	C) 2:1	D) 3:1	E) None
Sol.   Let man’s rate upstream be x kmph. Then, his rate downstream = 2x kmph.   ∴ (Speed in still water) : (Speed of stream)   = [2x + x / 2] : [2x - x / 2]   3x / 2 : x / 2 = 3:1.   Answer 3:1
<result>D</result>
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