Task: Question Answering
Input (English): Problem: 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 : 
Options: a ) 1 : 2 , b ) 2 : 5 , c ) 6 ' ' 2 , d ) 3 : 1 , e ) 4 : 7
Output (English): d