Jake C. answered 02/24/23
Math Student - Helping Math Students
Greetings Anthony,
Assuming the interest rate is fixed we are going to use this formula m = (P*r(1+r)n) / ((1+r)n-1)
Defining our variables:
m: Monthly payment
P: Principal amount (the amount taken out as a loan)
r: Interest rate per month
n: Total amount of payments due
To find P, we use the information regarding their down payment. With $807,000 being 20% of the down payment we can multiply $807,000 * 5 to find out the total price of their expensive home. We then minus $807,000 from this number to find the amount they take out as a loan which is $3,228,000. Hopefully one day I'll be able to afford a home like Raymond and Kevin B)
P = $3,228,000
To find r, we convert 3.15% to a decimal, .0315. We then divide this by 12 to find the interest due per month.
r = .0315 / 12
to find n, we multiply the total amount of years by months per year. 30 * 12 = 360
n = 360
Plugging this information into our formula results in the monthly payments.
(32288000*(.0315/12)*(1+(.0315/12)360)) / ((1+(.0315/12))360-1) = 13871.90657607
We then round this number to the nearest cent resulting in:
$13871.91 as their anticipated monthly payment.
Hope this helps :)

Peter R.
02/25/23