Answer:
Approximately 12.25%
Explanation:
The compound interest formula is:
Final balance = Principal * (1 + interest rate/number of times interest compounded per year)^(number of times interest compounded per year * years elapsed)
If we want our final balance to be twice our principal, our formula looks like:

We can divide our principal from both sides to get the following equation:

Since anything divided by 1 is itself, we can simplify a little further to:

Now, we need to solve for r. We can start by taking the sixth root of both sides.
![\sqrt[6]{2} = 1 + r](https://img.qammunity.org/2022/formulas/mathematics/high-school/bouzrpqw7132aun1g236s8q8swd0oj72z3.png)
Then subtract 1 from both sides:
![\sqrt[6]{2} -1 = r](https://img.qammunity.org/2022/formulas/mathematics/high-school/1z33d6w8xdu4fm0zeburnx88cidsffsudz.png)
Finally, we can use a calculator to get a decimal approximation:
0.1225 ≅ r