Country A has 3300 labor units and can produce manufactures and food. A's producers take 2 units of labor to produce a unit of manufactures and 6 units to produce a unit of food. Country B has 2100 units of labor and takes 3 units of labor to produce a unit of manufactures and 7 units to produce a unit of food. At what price of food in terms of manufactures would A and B respectively supply food? Would trade take place between A and B in David Ricardo's world? How many manufactures could A supply?