Task: Question Answering
Input (English): Problem: a and b together can do a piece of work in 3 days . if a alone can do the same work in 20 days , then b alone can do the same work in ? 
Options: a ) 0.28 days , b ) 0.45 days , c ) 0.55 days , d ) 0.25 days , e ) 0.15 days
Output (English): a