Additional exercise: A firm producing health product, Cereal K, using several elements. Two of the elements, wheat and rice, producing vitamins A and B. The firm wants to know how many grams of wheat and rice it must put into each box of Cereal K to meet the minimum standard of 48 mg Vitamin A and 12 mg Vitamin B while minimizing the cost. Each gram of wheat can give 8 mg Vitamin A and 1 mg Vitamin B, while each gram rice gives 6 mg Vitamin A and 12 mg Vitamin B. Each gram wheat cost 50 cent and each gram rice cost 30 cent. Form a linear programming model to solve the above