3. A patient in a hospital is required to have at least 84 units of drug A and 120 units of drug B each day. Each gram of substance M contains 10 units of drug A and 8 units of drug B, and each gram of substance N contains 2 units of drug A and
4 units of drug 8. Substance M is also highly expensive which means not more than 10 grams of it may be used.
Unfortunately both M and N contain an undesirable drug C, 3 units per gram in M and 4 units per gram in N. How many
grams of substances M and N should be mixed to meet the minimum daily requirements at the same time minimize the
intake of drug C? What would be the minimum amount of drug C preset in the mixture?