1. A chemical firm makes two brands of fertilizer. Their regular brand contains nitrates, phosphates, and potash in the ratio 3:6:1 (by weight) and their super brand contains these three ingredients in the ratio 4:3:3. Each month the firm can rely on a supply of 9 tons of nitrates, 13.5 tons of phosphates, and 6 tons of potash. Their manufacturing plant can produce at most 25 tons of fertilizer per month. If the firm makes the profit of P15000 on each ton of regular fertilizer and P24000 on each ton of the super grade, what amounts of each grade should be produced in order to yield the maximum profit? (the table is found in file above).