Please help -
Monthly payments on a 30 year basis for a $32,000 loan at 9% amount to monthly payments of $257.48.
Prof gave me formula:
m= (Rate*Cost)/(1200*(1-(1+((rate/1200)^(-12* years)))))
I keep plugging it in but I am NOT getting what he got?!? Can someone explain how this formula works?

Question

Please help -
Monthly payments on a 30 year basis for a $32,000 loan at 9% amount to monthly payments of $257.48.
Prof gave me formula:
m= (Rate*Cost)/(1200*(1-(1+((rate/1200)^(-12* years)))))
I keep plugging it in but I am NOT getting what he got?!?  Can someone explain how this formula works?

anonymous · Answer

let me type it in with judicious use of parentheses and see what we get hold on

anonymous · Answer

ok i think the formula has a mistake in it

anonymous · Answer

where did the 1200 come from?

anonymous · Answer

My professor gave it to me.  I have no idea.....I have tried solving it every which way but I do not get his answer.

anonymous · Answer

the one i know is 
$$\frac{3200\times \frac{.09}{12}}{1-(1+\frac{.09}{12})^{-360}}$$

anonymous · Answer

make sure to use -360 and not -12 *30 because that is liable to mess you up in the calculator

anonymous · Answer

ok (i guess maybe it was a really bad typo?)
Thank you so much!

anonymous · Answer

here is what i got, it matches up as you can see http://www.wolframalpha.com/input/?i=32000%28.09%2F12%29%2F%281-%281%2B%28.09%2F12%29%29^%28-360%29%29%29

anonymous · Answer

Yeah! Ok, I'll shoot him an email to let him know and continue forward this way.
Thanks again!!!!!!