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 1 liters a minute into the cistern , and it is emptied in 24 minutes . how many liters does the cistern hold ? 
Options: a ) 480 , b ) 120 , c ) 289 , d ) 270 , e ) 927
Output (English): b