In: Finance
Joe can purchase one of two annuities.
Annuity 1: A 10 year decreasing annuity immediate with annual
payments
of 10, 9, 8, ..., 2, 1.
Annuity 2: A perpetuity immediate with annual payments: the
perpetuity
pays 1 in year 1, 2 in year 2, 3 in year 3, ...., 11 in year 11.
After year 11, the
payments remain constant at 11.
At an annual e§ective interest rate of i, the present value of
Annuity 2 is
twice the present value of Annuity 1. Calculate the present value
of Annuity 1
at this annual e§ective interest rate of i.
We use excel solver to solve the problem
Initially, we assume any random effective interest rate of i ( 5% assumed)

Here, we find the terminal value using the formula = Annuity in year 11 + (Annuity in year 11 /Interest rate)
NPV is found using NPV function in excel => NPV = NPV (Interest rate, All cash-flows)
We input the following constraints in excel solver

Solving we get the Effective interest rate = 9.30% and PV of Annuity 1 = $39.42

| Effective interest rate 'i' = | 9.30% | ||
| NPV | $39.42 | $78.84 | |
| Year | |||
| 1 | 10 | 1 | |
| 2 | 9 | 2 | |
| 3 | 8 | 3 | |
| 4 | 7 | 4 | |
| 5 | 6 | 5 | |
| 6 | 5 | 6 | |
| 7 | 4 | 7 | |
| 8 | 3 | 8 | |
| 9 | 2 | 9 | |
| 10 | 1 | 10 | |
| Terminal value at year 11 | 0 | 129.2593 |
Hence, the Present Value of Annuity 1 at the required annual effective interest rate of 9.30% = $39.42