A clinical firm has two factories, a northern factory and a western factory, where they make expensive anti-itch injections and topical cream. Every hour, the northern factory makes 800 g of anti-itch injections and 700 g of topical cream. Every hour, the western factory makes 650 g of anti-itch injections and 750 g of topical cream. The northern factory requires 40 units of plastic per hour while the western factory requires 35 units of plastic to manufacture the packaging. The clinical firm has available 60,000 units of plastic. Further, they must make at least 800,000 g of anti-itch injections and 700,000 g of topical cream. How many hours should each factory be run to minimize the total time needed?