Please list all steps and assumptions - you have to show the model, its solution, and your interpretation of the output.

A store in Rio Piedras has to make room for new outfits by liquidating 200 of its shirts and 100 pairs of pants from last season. They have decided to put together two offers, A and B. Offer A is a package of one shirt and a pair of pants which will sell for $30. Offer B is a package of three shirts and a pair of pants, which will sell for $50. The store does not want to sell less than 20 packages of Offer A and less than 10 of Offer B. At least 60% of the products have to be shirts. Formulate a LP model to determine how many packages of each do they have to sell to maximize the money generated from the promotion?