Task: Question Answering
Input (English): Problem: a and b complete a work in 30 days . a alone can do it in 40 days . if both together can do the work in how many days ? 
Options: a ) 1.0875 days , b ) 0.1873 days , c ) 0.0673 days , d ) 0.0583 days , e ) 0.0773 days
Output (English): d