The formula for the monthly payment.....
[tex]M= \frac{P(1+r)^nr}{[(1+r)^n] -1}[/tex] , where P = the principal amount, r = the monthly interest rate and n = the total number of months.
Here annual interest rate is given as 4.5%
So, the monthly interest rate [tex]=\frac{4.5\%}{12}= 0.375\% = 0.00375[/tex]
Total number of months [tex]= (30*12)months=360 months[/tex]
Also given that, the principal amount is $225000
a. So, the monthly payment will be.....
[tex]M= \frac{P(1+r)^nr}{[(1+r)^n] -1}\\ \\ M= \frac{225000(1+0.00375)^3^6^0*0.00375}{(1+0.00375)^3^6^0 -1}\\ \\ M= \frac{225000(1.00375)^3^6^0*0.00375}{(1.00375)^3^6^0 -1} \\ \\ M \approx 1140[/tex]
Thus, the monthly payment will be approximately $1140
b. The total amount paid over the term of the loan will be: [tex]\$ 1140*360 months = \$ 410400[/tex]
c. As the principal amount was $225000 , so the amount of interest [tex]= (\$ 410400- \$ 225000)= \$ 185400[/tex]
So, the percentage of amount that is paid toward the principal [tex]=\frac{225000}{410400}*100\% =54.82\%[/tex]
and the percentage of amount that is paid toward the interest [tex]=\frac{185400}{410400}*100\%=45.18\%[/tex]