Independent solution

How to solve this Annuities question

Setup

Setup

Write the declining payment and its accumulation time to the final receipt date.

Pk=100(0.9)k1P_k=100(0.9)^{k-1}
F20=k=120Pk(1.03)20kF_{20}=\sum_{k=1}^{20}P_k(1.03)^{20-k}

Model

Model

Recognize the terminal-value expression as a finite geometric sum.

F20=100k=120(0.9)k1(1.03)20kF_{20}=100\sum_{k=1}^{20}(0.9)^{k-1}(1.03)^{20-k}

Compute

Compute

Evaluating the twenty accumulated contributions gives 1295.795831.

F20=1295.79583083F_{20}=1295.79583083

Answer

Answer

The savings balance is approximately 1,296, selecting choice D.

F201296(D)\boxed{F_{20}\approx1296\quad\text{(D)}}