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A produce grower is purchasing fertilizer containing three nutrients: A, B, and C. The minimum weekly requirements are 80 units of A, 120 units of B, and 240 units of C. There are two blends of fertilizer on the market: Blend I costs $8 per bag, and contains 2 units of A, 6 units of B, and 4 units of C. Blend II costs $10 per bag, and contains 2 units of A, 2 units of B, and 12 units of C. How many bags of each blend should the grower buy each week in order to minimize the cost while still meeting the nutrient requirements?