A company uses a blend of nitrogen and phosphorus to produce two of its popular fertilizers.

- Their "AP" blend must be at least 45% nitrogen and sells for $160 per kg.

- Their "PSP" blend must be at least 65% phosphorus and sell for $1 per kg.

- They can purchase up to 7,000 kg of nitrogen at $50 per kg, and up to 10,000 kg of phosphorus at $20 per kg.

- Assume that they can sell all fertilizer produced.

What is the optimal blending plan to maximize profit? Build the model in Excel, and use Excel Solver for the solution.