A uniform gradient cash flow contains a first payment of $500 at the end of the first year, $600 payment at the end of the second year, $700 payment at the end of the third year, $800 payment at the end of the fourth year, and so on. There are a total of 15 payments. The annual interest rate is 8%. Determine: (a) the present, (b) the future, and (c) the uniform annual amounts that are equivalent to the cash flow.