Task: Question Answering
Input (English): Problem: a can do a particular work in 6 days . b can do the same work in 8 days . a and b signed to do it for rs . 2400 . they completed the work in 3 days with the help of c . how much is to be paid to c ? 
Options: a ) s . 300 , b ) s . 600 , c ) s . 420 , d ) s . 400 , e ) s . 480
Output (English): a