Question

Tanner has invested $500 for college. what rate of return must tanner earn for his investment to double in six years

Answer 1

This is answered using the Rule of 72. This is the easiest way to know how long an investment will take to double, given a fixed annual rate of interest
The rule of 72 is the period to double multiplied by the interest rate equal 72.

So to do this: Just divide 72 and 6. 72/6 = 12% would be the rate of return