You have just purchased an increasing annuity-immediate for 50,000 that makes twenty annual payments as follows: - P,2P,,10P in years 1 through 10 ; and - 10P(1.05),10P(1.05)2,,10P(1.05)10 in years 11 through 20 . The annual effective interest rate is 7% for the first 10 years and 5% thereafter. Calculate P