Professor's Annuity Corp. offers a lifetime annuity to retiring professors. For a payment of $83,000 at age 65, the firm will pay the retiring professor $675 a month until death. a. If the professor's remaining life expectancy is 20 years, what is the monthly interest rate on this annuity? (Do not round intermediate calculations. Enter your answer as a percent rounded to 2 decimal places.) Monthly rate on annuity 0.64 % b. What is the effective annual interest rate? (Do not round intermediate calculations. Round your answer to 2 decimal places.) Effective annual rate 7.90 % c. If the monthly interest rate is 0.50%, what monthly annuity payment can the firm offer to the retiring professor? (Do not round intermediate calculations. Round your answer to 2 decimal places.) Monthly annuity payment I now have $23,000 in the bank earning interest of 0.50% per month. I need $33,000 to make a down payment on a house. I can save an additional $100 per month. How long will it take me to accumulate the $33,000? (Do not round intermediate calculations. Round your answer to 2 decimal places. Use a financial calculator or Excel.) Time required 294.00 months