Two types of food X and Y re mixed to prepare a mixture is such a way that the mixture contains at least 10 units of vitamin A, 12 units of vitamin B and 8 units of vitamin X. These vitamines are avialalbe in 1kg of food as per table below. 1kg of food X costs Rs 16 and 1kg of food Y costs Rs 20. Formulate the L. P. P. so as to determine the least cost of the mixture containing the required amound of vitamins.