Independent solution

How to solve this Equivalent Interest Measures question

Setup

Setup

A 12% nominal discount rate convertible quarterly has quarterly discount rate 3%, so each quarter accumulates by 1 divided by 0.97.

d(4)/4=0.03d^{(4)}/4=0.03

Model

Model

Equate the two account balances after n years. Fund X has 4n quarterly periods, and Fund Y accumulates under force 0.08.

100(0.97)4n=200e0.08n100(0.97)^{-4n}=200e^{0.08n}

Compute

Compute

Take natural logarithms and isolate n.

n[4ln(0.97)0.08]=ln2n[-4\ln(0.97)-0.08]=\ln 2
n=16.5679n=16.5679

Answer

Answer

The balances meet after approximately 16.6 years, so the answer is B.

n16.6(B)\boxed{n\approx16.6\quad\text{(B)}}