Task: Question Answering
Input (English): Problem: john had a stock of 800 books in his bookshop . he sold 62 on monday , 62 on tuesday , 60 on wednesday , 48 on thursday and 40 on friday . what percentage of the books were not sold ? 
Options: a ) 78 % , b ) 66 % , c ) 62 % , d ) 64 % , e ) 60 %
Output (English): b