Independent solution

How to solve this Annuities question

Setup

Setup

A decrease of r percent is a geometric growth rate of negative r divided by 100.

g=r/100g=-r/100

Model

Model

Apply the growing-perpetuity-immediate price formula.

16000=10000.057g=10000.057+r/10016000=\frac{1000}{0.057-g}=\frac{1000}{0.057+r/100}

Compute

Compute

Solving the denominator equation gives r = 0.550000%.

0.057+r/100=1/160.057+r/100=1/16
r=0.55000000r=0.55000000

Answer

Answer

The annual payment decrease is approximately 0.55%, selecting choice B.

r0.55%(B)\boxed{r\approx0.55\%\quad\text{(B)}}