Using the rule of 72, approximate the following: lf the value of land in an area is increasing 8 percent a year, how long will it take for property values to double? (Round your answer to 1 decimal place.) If you earn 12 percent on your investments, how long would it take for your money to double? (Round your answer to 1 decimal place.) At an annual interest rate of 4 percent, how long would it take for your savings to double? (Round your answer to 1 decimal place.)