An ordinary annuity has a periodic payment of $500 per year for 10 years. (a) Use EXCEL to find the present value of this annuity given a discount rate of 7%. (b) Set up a table with two columns. The first column has interest rates from 7% to 15% by increments of 1%. The second column has the present value of the annuity for each of the interest rates from 7% to 15%. (c) Graph the information in the two columns of (b)