(Future value of an annuity) Upon graduating from college 40 years ago, Dr. Nick Riviera was already planning for his retirement. Since then, he has made deposits into a retirement fund on a quarterly basis in the amount of $400. Nick has just completed his final payment and is at last ready to retire. His retirement fund has earned 6 percent compounded quarterly. Use five decimal places for the periodic interest rate in your calculations. a. How much has Nick accumulated in his retirement account? b. In addition to this, 20 years ago Nick received an inheritance check for $20,000 from his beloved uncle. He decided to deposit the entire amount into his retirement fund. What is his current balance in the fund