Use PMT $=\frac{P(\frac{r}{n})}{[1-(1+\frac{r}{n}{)}^{-nt}]}$ to determine the regular payment amount, rounded to the nearest dollar. The price of a small cabin is $$70,000.$ The bank requires a $5\%$ down payment. The buyer is offered two mortgage options: $20-$year fixed at $9\%$ or $30-$year fixed at $9\%.$ Calculate the amount of interest paid for each option. How much does the buyer save in interest with the $20-$year option?

Find the monthly payment for the $20-$year option.

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$($Round to the nearest dollar as needed.$)$