Question

A $104,000 selling price with $24,000 down at 81⁄2% for 25 years results in a monthly payment of

Answer 1

Okay so first I am taking it that you have to subtract 24k from the 104k which brings it to 80,000.
I am also taking it that the 8.5% is suppose to be in decimal form which makes it .085%
Take the 80,000 and use the monthly payment formula, which is really easy to use.
Monthly payment should be 644.18

Answer 2

$\bf \qquad \qquad \textit{Future Value of an ordinary annuity} \\\\ FV=pymnt\left[ \cfrac{\left( 1+\frac{r}{n} \right)^{nt}-1}{\frac{r}{n}} \right] \\\\ \qquad \begin{cases} FV=\textit{future value}\to & \begin{array}{llll} 104,000\\ -24,000\\ -----\\ 80,000 \end{array}\\ pymnt=\textit{periodic payments}\\ r=rate\to 8\frac{1}{2}\%\to \frac{8.5}{100}\to &0.085\\ n= \begin{array}{llll} \textit{times it compounds per year}\\ \textit{monthly payments, means 12} \end{array}\to &12\\ t=years\to &25 \end{cases}$

$\bf thus \\\\ 80,000=pymnt\left[ \cfrac{\left( 1+\frac{0.085}{12} \right)^{12\cdot 25}-1}{\frac{0.085}{12}} \right]$

solve for "pymnt"