Task: Question Answering
Input (English): Problem: a person can row at 9 kmph and still water . he takes 4 1 / 2 hours to row from a to b and back . what is the distance between a and b if the speed of the stream is 1 kmph ? 
Options: a ) 33 , b ) 77 , c ) 26 , d ) 28 , e ) 20
Output (English): e