Task: Question Answering
Input (English): Problem: x alone can do a piece of work in 15 days and y alone can do it in 10 days . x and y undertook to do it for rs . 720 . with the help of z they finished it in 5 days . how much is paid to z ? 
Options: a ) rs . 360 , b ) rs . 120 , c ) rs . 240 , d ) rs . 300 , e ) none
Output (English): b