$($Complex annuity$)$ Upon graduating from college $35$ years$$ ago, Dr$.$ Nick Riviera was already thinking of retirement. Since$$ then, he has made deposits into his retirement fund on a monthlymonthly basis in the amount of $$$$160.$ Nick has just completed his final payment and is at last ready to retire. His retirement fund has earned $9\mathrm{.}3\%$ interest compounded monthly.

a$.$ How much has Nick accumulated in his retirement$$ account?

b$.$ In addition to all$$ this, $2020$ years$$ ago, Nick received an inheritance check for $$$$15000$ from his beloved uncle. He decided to deposit the entire amount into his retirement fund. What is his current balance in the$$ fund?