Need step by step calculation

A concrete company makes three kinds of mixtures. They can sell up to 400 tons of each mixture at the following prices (per ton): mixture A, $100; mixture B, $120; mixture C, $200. The company purchases raw material at $50/ton. Each ton of raw material can be used to produce either 1 ton of mixture A or 1 ton of mixture B. For a cost of $30/ton processed, mixture A can be converted to .6 tons of mixture B and .4 tons of mixture C. For a cost of $20/ton processed, mixture B can be converted to .8 tons of mixture C. Formulate a linear program (with clearly defined decision variables and constraints) that maximizes the company's profit