a manufacturer makes 2 minute,6 minute and 9 minute film developers.each ton of 2 minute developer requires 6 minutes in plant a and 24 minute in plant b.each ton of 6 minute developer requires 12 minutes in plant a and 12 minutes in plant b.each ton of 9 minute developer requires 12 minutes in plant a and 12 minutes in plant b. if plant a is available 10 hours per day and plant b is available 16 hours per day.how many tons of each type of developer can be produced so that the plant are fully used.