Answer :
To answer this problem, we need to use the compound interest formula, which is
[tex]A=P(1+\frac{r}{n})^{nt}[/tex]Where A represents the final amount, P represents the principal(initial investment), r represents the interest rate in decimals, n represents the number of times interest is compounded per unit t, and t the amount of time.
We have the final balance of Harrison's account, which is our value A
[tex]A=155.59[/tex]The interest rate is 9.4%. To convert a percentage to a decimal, we just divide the percentage value by 100.
[tex]r=9.4\%=\frac{9.4}{100}=0.094[/tex]The initial investment was two years ago, therefore, the time period is 2.
[tex]t=2[/tex]And since the interest is compounded anually and the time period unit is year, we have
[tex]n=1[/tex]Plugging all those values in the formula, we have
[tex]155.59=P(1+\frac{0.094}{1})^{1\cdot2}[/tex]Solving for P, we have
[tex]\begin{gathered} 155.59=P(1+\frac{0.094}{1})^{1\times2} \\ 155.59=P(1.094)^2 \\ P=130.001102908... \\ P\approx130.00 \end{gathered}[/tex]The initial investment was $130.00.