a$.$ If the interest rate is $5\mathrm{.}0\%$ per year, approximately how long will it take for your money to quadruple in value?

Note: Use the Rule of $72.$ Round your answer to $2$ decimal places.

Number of years

b$.$ If the inflation rate is $3\mathrm{.}5\%$ per year, what will be the change in the purchasing power of your money over this period? Note: Use the Rule of $72$ to compute the number of years. Do not round intermediate calculations. Enter your ans percent rounded to $2$ decimal places.

Purchasing power by

$\%$