You are considering a luxury apartment building project that requires an investment of $12,500,000. The building has 50 units. You expect that the maintenance cost for the apartment building will be $250,000 in the first year, and to rise to $300,000 in the second year, and to continue to increase by $50,000 in subsequent years. The cost to hire a manager for the building is estimated to be $80,000 per year. After five years of operation, the apartment building can be sold for $14,000,000. What annual rent per apartment unit will provide a return on investment of 15%? Assume that the building will remain fully occupied during the five years.