Question: Lauren Moore has sold her business for 500,000 and wants to invest in condominium units and land. She estimates that she will receive an annual return of 8,000 for each condiminum and 6,000 for each acre of land. A condominium unit costs 70,000 and land costs 30,000 per acre. A condominium will cost her 1,000 per unit, an acre of land will cost 2,000 for maintenance and upkeep, and 14,000 has been budgeted for these annual expenses. Lauren wants to know how much to invest in condominiums and land to maximize her annual return.

Formulate a mixed integer programming model for this problem and solve using a computer.