Two perpetuities have the same annual effective interest rate. Perpetuity A pays $8.20 at the end of each year for the first 20 years and then $3.70 at the end of each year thereafter. Perpetu ity B is a perpetuity-immediate which has a level annual payment of $6.40. At time t 0, the present value of perpetuity A is equal to that of perpetuity B. What is the effective annual interest rate i? (in percents rounded to 2 decimal places.) Answer =