ANSWER:
0.06 or 6% as a percentage.
STEP-BY-STEP EXPLANATION:
We have that the related formula in this case is the following:
[tex]\begin{gathered} A=P\cdot(1+r)^t \\ A\text{ = Amount} \\ P\text{ = Principal} \\ r\text{ = interest rate} \\ t\text{ = time} \end{gathered}[/tex]Replacing each value and solving for r
[tex]\begin{gathered} 1220=610\cdot(1+r)^{12} \\ (1+r)^{12}=\frac{1220}{610} \\ (1+r)^{12}=2 \\ 1+r=\pm\sqrt[12]{2} \\ r=\pm\sqrt[12]{2}-1 \\ r_1=0.06 \\ r_2=-2.06 \end{gathered}[/tex]Since the interest cannot be negative, the correct interest is 0.06 or 6% as a percentage.
