The question is an annuity question with the present value of the annuity given.
The
present value of an annuity is given by PV = P(1 - (1 + r/t)^-nt) /
(r/t) where PV = $61,600; r = interest rate = 9.84% = 0.0984; t = number
of payments in a year = 6; n = number of years = 11 years and P is the
periodic payment.
61600 = P(1 - (1 + 0.0984/6)^-(11 x 6)) / (0.0984 / 6)
61600 = P(1 - (1 + 0.0164)^-66) / 0.0164
61600 x 0.0164 = P(1 - (1.0164)^-66)
1010.24 = P(1 - 0.341769) = 0.658231P
P = 1010.24 / 0.658231 = 1534.78
Thus, Niki pays $1,534.78 every two months for eleven years.
The total payment made by Niki = 11 x 6 x 1,534.78 = $101,295.48
Therefore, interest paid by Niki = $101,295.48 - $61,600 = $39,695.48
