The monthly payment that amortizes a loan of A dollars in t years when the interest rate is r per year is given by
P = f(A, r, t) = Ar / (12(1 - (1 + r/12)^-12t))
Find the monthly payment for a home mortgage of $225,000 that will be amortized over 30 years with an interest rate of 5.15% per year.