Task: Question Answering
Input (English): Problem: a boat sails 15 km of a river towards upstream in 5 hours . how long will it take to cover the same distance downstream , if the speed of current is one - fourth the speed of the boat in still water ? 
Options: a ) 7 h , b ) 3 h , c ) 4 h , d ) 2 h , e ) 9 h
Output (English): b