Independent solution

How to solve this Annuities question

Setup

Setup

Decompose the payments into a level perpetuity of 150 and an increasing perpetuity with unit increments scaled by 10.

5000=150i+10i25000=\frac{150}{i}+\frac{10}{i^2}

Model

Model

Multiply by i squared to obtain a quadratic in the positive yield.

5000i2150i10=05000i^2-150i-10=0

Compute

Compute

The positive root is i = 6.216991%.

i=0.0621699057i=0.0621699057

Answer

Answer

The annual effective rate is approximately 6.2%, selecting choice B.

i6.2%(B)\boxed{i\approx6.2\%\quad\text{(B)}}