if you divide 45 by 3 you get 15 and if you divide 12 by 3 you get four then you multiply it by 4 because there's 4 15 minutes in an hour and you do the same to the 3 since that's how many you can get in an hour and then you just multiply 16 by 6:00 because you can do 16 bread in an hour and then 16 * 6 for the amount of hours that you're baking