The facilities manager at Deakin University is planning to apply fertilizer to a grass area in front of the Law building. The grass needs nitrogen, phosphorus, and potash in at least the amounts given in the following table. Mineral Nitrogen Phosphorus Potash Minimum weight (kg) 6 7 9 Three kinds of commercial fertilizers are available, with mineral content and prices per 1,000 kilograms as given in the following table. Fertilizer Nitrogen 20 Phosphorus 10 Potash 5 15 Price (5) 10 16 A 10 Three kinds of commercial fertilizers are available, with mineral content and prices per 1,000 kilograms as given in the following table. Fertilizer B C Nitrogen 20 10 15 Phosphorus 10 5 10 Potash 5 15 5 Price ($) 10 16 14 The facilities manager wants to purchase enough fertilizer to satisfy the requirements at minimum cost. Formulate the algebraic model for this problem by writing down the decision variables, objective function and constraints