1.  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 :
A. 2 : 1
B. 3 : 1
C. 3 : 2
D. 4 : 3

Answer: Option B

Explanation:

Let man's rate upstream be x kmph.

Then, his rate downstream = 2x kmph.

 (Speed in still water) : (Speed of stream)

 = 2x + x : 2x - x
2 2

   = 3x : x
2 2

   = 3 : 1.