Task: Question Answering
Input (English): Problem: a , b and c can do a work in 15 , 20,45 days respectively . in how many days they can complete the work together . 
Options: a ) 5.2 days , b ) 9.2 days , c ) 8.2 days , d ) 6.2 days , e ) 7.2 days
Output (English): e