(Complex annuity) Upon graduating from college 30 years ago, Dr. Nick Riviera was already thinking of retirement. Since then, he has made deposits into his retirement fund on a semiannual basis in the amount of $900. Nick has just completed his final payment and is at last ready to retire. His retirement fund has earned 9.9% interest compounded semiannually. a. How much has Nick accumulated in his retirement account? b. In addition to all this, 20 years ago, Nick received an inheritance check for $25,000 from his beloved uncle. He decided to deposit the entire amount into his retirement fund. What is his current balance in the fund? a. Since graduating from college 30 years ago, Dr. Nick Riviera has made deposits into his retirement fund on a semiannual basis in the amount of $900. If his retirement fund has eamed 9.9% interest compounded semiannually, how much has Nick accumulated in his retirement account? (Round to the nearest cent.)