How many years to double investment if interest rate is .10%

How the Rule of 72 Works. For example, the Rule of 72 states that $1 invested at an annual fixed interest rate of 10% would take 7.2 years ((72/10) = 7.2) to grow to $2. In reality, a 10% investment will take 7.3 years to double ((1.107.3 = 2). The Rule of 72 is reasonably accurate for low rates of return.

Step-by-step explanation:

For example, if you invest $10,000 at 10 percent compound interest, then the “Rule of 72” states that in 7.2 years you will have $20,000. You divide 72 by 10 percent to get the time it takes for your money to double. The “Rule of 72” is a rule of thumb that gives approximate results