Using the Rule of 72, approximate the following amounts. a. If the value of land in an area is increasing 6 percent a year, how long will it take for property values to double? b. If you earn 10 percent on your investments, how long will it take for your money to double? (Round your answer to 1 decimal place.) c. At an annual interest rate of 5 percent, how long will it take for your savings to double? (Round your answer to 1 decimal place.)