please answer all!(:

(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 semiannually 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 12 percent compounded semiannually. 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, 15 years ago Nick received an inheritance check for $15,000 from his beloved uncle. He decided to deposit the entire amount into his retirement fund. What is his current balance in the fund? a. The amount Nick has accumulated in his retirement account is (Round to the nearest cent.) (Annuity number of periods) Alex Karev has taken out a $190,000 loan with an annual rate of 9 percent compounded monthly to pay off hospital bills from his wife Izzy's illness. If the most Alex can afford to pay is $2,500 per month, how long will it take to pay off the loan? How long will it take for him to pay off the loan if he can pay $3,000 per month? Use five decimal places for the monthly percentage rate in your calculations. a. If Alex can pay $2,500 per month, the number of years it takes for him to pay off the loan is years. (Round to one decimal place.)