1. Define data
P = 3000 dollars
r = 4.25%
A = 5600 dollars
n = 2
2. Equation
[tex]A=P(1+\frac{r}{n})^{nt}[/tex][tex]5600=3000(1+0.0425/2)^{2t}[/tex][tex]\begin{gathered} \frac{5600}{3000}=(1.02125)^{2t} \\ 1.86=(1.02125)^{2t} \end{gathered}[/tex]Solving for t
[tex]t=14.8\text{ years}[/tex]