Independent solution

How to solve this Annuities and Perpetuities question

Setup

Setup

Value the perpetual year-end income and the six beginning-of-year investments separately at time zero.

PVincome=1000.1025=975.6098PV_{\rm income}=\frac{100}{0.1025}=975.6098

Model

Model

Because each later investment grows by 5% but is discounted at 10.25%, their present values form a six-term geometric series.

PVinvest=Xk=05(1.051.1025)k=5.3295XPV_{\rm invest}=X\sum_{k=0}^{5}\left(\frac{1.05}{1.1025}\right)^k=5.3295X

Compute

Compute

A zero net present value requires the investment series to equal 975.61; dividing by its factor gives 183.06.

NPV=0X=975.60985.3295=183.06NPV=0\Longrightarrow X=\frac{975.6098}{5.3295}=183.06

Answer

Answer

The initial investment is approximately 183, corresponding to choice A.

X183(A)\boxed{X\approx183\quad\text{(A)}}