At a specific oil refinery, the refining process requires the production of 1.5 gallons of gasoline for each gallon of fuel oil. To meet the refinery's demand in the winter, the refinery will need to produce at least three million gallons of fuel oil a day. On the other hand, the demand for gasoline is predicted be no more than five million gallons a day. If gasoline sells for $1.80 per gallon and fuel oil sells for $1.60 per gallon, how much of each should be produced to maximize revenue, and how much revenue will the refinery earn?