Task: Question Answering
Input (English): Problem: two pipes a and b separately fill in 15 / 2 min and 5 min respactively and third pipe c can empty of 14 l / m if all the pipes are open when the cistern is full , it is emptied in 1 hr . how many litres does the cistern hold ? 
Options: a ) 40 , b ) 30 , c ) 50 , d ) 80 , e ) 54
Output (English): a