Task: Question Answering
Input (English): Problem: a carpenter worked alone for 1 day on a job that would take him 7 more days to finish . he and another carpenter completed the job in 4 more days . how many days would it have taken the second carpenter to do the complete job working alone ? 
Options: a ) 16 , b ) 7 , c ) 9 , d ) 14 , e ) 24
Output (English): a