Task: Question Answering
Input (English): Problem: george does 3 / 5 th of a piece of work in 9 days . he then calls in paul , and they finish the work in 4 days . how long would paul take to do the work by himself ? 
Options: a ) 30 , b ) 40 , c ) 50 , d ) 60 , e ) 70
Output (English): a