A firm has two types of animals, species I and species I. The owner provides two types of food, A and B for these animals. Species I requires 2 units of food A and 2 units of food B; and species II requires 4 units of food A and 2 units of food B. If the owner has 100 units of each food, find the maximum number of animals that can be supported. Use graphical method to solve the problem