Task: Question Answering
Input (English): Problem: a cistern has a leak which would empty the cistern in 20 minutes . a tap is turned on which admits 10 liters a minute into the cistern , and it is emptied in 24 minutes . how many liters does the cistern hold ? 
Options: a ) 4800 , b ) 1200 , c ) 1680 , d ) 1100 , e ) 1300
Output (English): b