1) What interest rate would you have to earn if you wanted to double an investment in 25 years?

2) 6 years ago, you invested $27,500. The investment has grown to $37,600. What is your average rate of return?

3) On January 1 of this year, you invested $350 at a rate of 5% compounded annually. If your tax rate is 30%, what will the tax on your investment be at the end of the year?