Mr. and Mrs. Rahman purchase a house of 115,000. They make a 20% down payment. With the balance amortized by a 30-year mortgage at an annual interest rate of 12.6% compounded monthly, the amount of their monthly mortgage payment is...
The down payment amount is 20% of $115,000, which is 0.2 * $115,000 = $<<0.2*115000=23000>>23,000.
The mortgage amount is $115,000 - $23,000 = $<<115000-23000=92000>>92,000.
The annual interest rate is 12.6%, so the monthly interest rate is 12.6% / 12 = 0.126 / 12 = 0.0105.
The number of payments over the 30-year period is 30 * 12 = <<30*12=360>>360.
Using the formula for the monthly mortgage payment, P = (r * PV) / (1 - (1 + r)^(-n)), where P is the monthly mortgage payment, r is the monthly interest rate, PV is the principal value (mortgage amount), and n is the number of payments, the monthly mortgage payment is (0.0105 * $92,000) / (1 - (1 + 0.0105)^(-360)).
Evaluating this expression gives a monthly mortgage payment of $<<((0.0105*92000)/(1-(1+0.0105)^(-360)))=809.2358442130427>>809.24 (rounded to the nearest cent). Answer: \boxed{809.24}.