2 * 200 * 300 = 200 + x * 300 + x = (200 + 300) * x
Solve for x.
You can see the answer and solution from the picture
Answer: 8%.
Step-by-step explanation:
To find this answer, use the compounding interest rate formula, or an exponential function:

Where A is the amount of money after t years, using P (principal) dollars as the investment and r as the rate.
We are trying to solve for r, so substitute the correct values for the other three variables:

Solving for r, we find that r to the ninth power equals 2.
Simplifying this, r is equal to 2^(1/9), or 1.08~. The interest rate was 8 percent.