A refinery produces both gaso- line and fuel oil, and sells gasoline for $4.00 per gallon and fuel oil for $3.60 per gallon. The refinery can produce at most 600,000 gallons a day but must produce at least 2 gallons of fuel oil for every gallon of gasoline. At least 150,000 gallons of fuel oil must be made each day for the coming winter. Determine how much of each type of fuel should be produced to maximize revenue.