53. A fertilizer company blends silicon and nitrogen to produce two types of fertilizers. Fertilizer 1 must be at least 40% nitrogen and sells for $70 per pound. Fertilizer 2 must be at least 70% silicon and sells for $40 per pound. The company can purchase up to 8000 pounds of nitrogen at $15 per pound and up to 10,000 pounds of silicon at $10 per pound. Assuming that all fertilizer produced can be sold, determine how the company can maximize its profit. Use SolverTable to explore the effect on profit of changing the minimum percentage of nitrogen required in fertilizer 1. Suppose the availabilities of nitrogen and silicon both increase by the same percentage from their current values. Use SolverTable to explore the effect of this change on profit.