Task: Question Answering
Input (English): Problem: micheal and adam can do together a piece of work in 20 days . after they have worked together for 15 days micheal stops and adam completes the remaining work in 10 days . in how many days micheal complete the work separately . 
Options: a ) 40 days , b ) 100 days , c ) 120 days , d ) 110 days , e ) 90 days
Output (English): a