An animal feed to be mixed from soybean meal and oats must contain at least 168 lb of protein, 27 lb of fat, and 14 lb of mineral ash. Each sack of soybeans costs $ 21 and contains 70 lb of protein, 9 lb of fat, and 7 lb of mineral ash. Each sack of oats costs $7 and contains 21 lb of protein, 7 lb of fat, and 1 lb of mineral ash. How many sacks of each should be used to satisfy the minimum requirements at minimum cost?

With reference to the solutions, following things may be noted1) homogeneous solutions comprises of single phase.2) heterogeneous solution comprises of more than one phase.3) in colloidal solution, solute is evenly distributed in solvent. in such system, it is difficult to separate solute and solvent.4) in suspension, there is an uneven distribution of solute in solvent. in such system, solute and solvent gets separated on standing long.    blood is a homogeneous and colloidal solution,salad dressing is a heterogeneous and suspension solution.