Task: Question Answering
Input (English): Problem: machine a and machine b are each used to manufacture 770 sprockets . it takes machine a 10 hours longer to produce 770 sprockets than machine b . machine b produces 10 percent more sprockets per hour than machine a . how many sprockets per hour does machine a produces ? 
Options: a ) 5 , b ) 7 , c ) 9 , d ) 10 , e ) 12
Output (English): b