The compound interest formula is given by nt A = P(1+ where A is the accumulated amount, after an initial investment of P dollars is invested for t years, at annual interest rate r, compounded n times per year. Use the formula above to determine how long it will take an initial investment of $6,750 to grow to $18,225, if the account earns 13.5% interest per year, compounded monthly. Round the solution to two decimal places. The account balance will reach $18,225 after years