A factory makes 1200 shirts every 6 hours. The factory makes shirts for 9 hours each workday. Enter the fewest number of workdays the factory will need to make 12,600

1200 shirts every 6 hours is the same as 200 shirts every hour.

then you multiply 200 by 9 (total number of hours in work day) to get 1800 (total number of shirt made in work day)

You're trying to achievce 12,600 shirts so just divide by 1800

12600/1800 = 7

it would take 7 days to make all those shirts