Jack London sold his condominium for $500,000 on September 14, 2007; he had paid $310,000 for it

Question:

Jack London sold his condominium for $500,000 on September 14, 2007; he had paid $310,000 for it in 1999. London collected the selling price as follows: 2007, $80,000; 2008, $320,000; and 2009, $100,000. London appropriately uses the installment-sales method. Prepare a schedule to determine the gross profit for 2007, 2008, and 2009 from the installment sale.