Five tanker ships have arrived at a chemical factory. They are carrying loads of liquid products that must not be mixed: 1200 tonnes of Benzol, 700 tonnes of Butanol, 1000 tonnes of Propanol, 450 tonnes of Styrene, and 1200 tonnes of THE. Nine tanks of different capacities are available on site. Some of them are already partially filled with a liquid. The following table lists the characteristics of the tanks (in tonnes). Into which tanks should the ships be unloaded (question 1) to maximize the capacity of the tanks that remain unused, or (question 2) to maximize the number of tanks that remain free? Table 9.6: Characteristics of tanks Tank 1 2 3 4 5 6. 7 8. 800 acity Current product 500 400 400 600 600 900 800 800 Benzol THE Quantity 100 300