Task: Question Answering
Input (English): Problem: 3 pumps , working 8 hours a day , can empty a tank in 2 days . how many hours a day must 15 pumps work to empty the tank in 1 day ? 
Options: a ) 3.5 , b ) 4.8 , c ) 5.1 , d ) 5.2 , e ) 6.3
Output (English): a