You are considering buying an Audi for $30,000, and your financing is quoted at 14% APR with monthly compounding. a. What rate do you need in order to use one of the following annuity formulas to find the monthly payments? PV(annuity of C for n periods with interest rate :) = Cx 1 (1 + r) or PV(growing perpetuity) = r-g b. What is the effective annual rate of interest for this financing? a. The rate that should be used for the formulas is r= (Round to six decimal places.) % b. The effective annual rate is (Round to four decimal places.)