A diet is to contain at least 80 units of vitamin A and 100 units of minerals. Two foods $F_{1} $ and $F_{2} $ are available. Food $F_1$ costs Rs 4 per unit food and $F_2$ costs Rs 6 per unit. One unit of food $F_{1} $ contains 3 units of vitamin A and 4 units of minerals. One unit of food $F_{2} $ contains 6 units of vitamin A and 3 units of minerals. Formulate this as a linear programming problem. Find the minimum cost for diet that consists of mixture of these two foods and also meets the minimal nutritional requirements.
