Atwenty-year annuity pays $2, 400 + 300k on the first day of the k-th month of the year. thus it pays $2,700 each january 1, $3,000 each february 1 ,. . , $6,000 each december 1. the first payment is on a january 1. find an expression for the value of this annuity just before the first payment and evaluate it if the annual effective interest rate is 5%.