Use the "Rule of 72" to determine the following: (a) The number of years it takes to accumulate $11,000 in a savings account when P= $5,500 and i = 12% per year. (b) The number of years it takes to accumulate $22,000 in a savings account when P = $5,500 and i = 12% per year. (c) The average annual interest rate, i, required to double an initial investment, P, in 17 years