The amount needed in the account when Frost retires is given by the annuity formula. Compounding is 2 times per year.
.. A = Pi/(n(1 -(1 +r/n)^(-nt)))
.. 17900 = P*.08/(2*(1 -(1 +.08/2)^(-2*12)))
.. 17900 = P*.04/(1 -(1.04^-24))
.. P ≈ 272,920.64
The compound interest formula can be used to find the present value required. 4015 days is 11 years (ignoring leap years), so the amount to deposit can be calculated from
.. A = P*(1 +r/n)^(nt)
.. 272,920.64 = P*(1 +.08/2)^(2*11) = P*1.04^22
.. P ≈ 115,160.33
We don't know about the company's obligation to Robert. To fulfill its obligation to Frost, it must deposit 115,160.33 today.
