Tammy takes out a loan of $400 on March 16, 2015. Up through December 5, 2015, the loan adds interest using an accumulation factor of a(t) = 1 + 0.05t + 0.005t 2, where t20 is in years. Thereafter, the loan compounds interest semiannually using an effective semiannual interest rate of 5%. If Tammy repays the loan (plus interest) in a lump sum payment on December 5, 2017, determine Tammy's repayment amount.