Question

Rebecca and Tom Payton have decided to buy a home that costs $200,000. The Paytons can put down 20% of the home's price. They have applied for a 15-year, 9% FRM to finance the balance. They Paytons have a combined gross annual income of $70,000. Answer the following questions about the Payton's decision.
What is the maximum amount the Paytons should pay each month, according to the 28% rule given in the Background Information in Day 1 of Project 2?

Answer 1

M = P * i (1+i)^n / ((1+i)^n − 1)

where:
M = Mortgage payment
P = Principal amount = $200,000 * 0.80 = $160,000
i = interest rate = 0.09/12 = 0.0075
n = number of payments = 12*15 = 180
M = $160,000 * 0.0075 * 1.0075^180 / (1.0075^180 − 1)
M = $1622.8265
Total paid = 180 * $1622.8365 = $292,108.77