Independent solution

How to solve this Reinvestment of Withdrawn Fund Interest question

Setup

Setup

The ten beginning-year deposits remain as principal because fund interest is paid out.

P10=10(10,000)=100,000P_{10}=10(10{,}000)=100{,}000

Model

Model

At the end of year t, t deposits produce 600t of interest, which is reinvested to year 10.

I10=t=110600t(1.04)10t=37,295.2711I_{10}=\sum_{t=1}^{10}600t(1.04)^{10-t}=37{,}295.2711

Compute

Compute

Combine principal and reinvested interest, then solve the ten-year yield on the original outlay.

F=137,295.2711F=137{,}295.2711
55,400(1+i)10=F55{,}400(1+i)^{10}=F

Answer

Answer

The annual effective yield is 9.5001%, choice B.

i=0.09500129.5%(B)\boxed{i=0.0950012\approx9.5\%\quad\text{(B)}}