Don't know how to figure this out myself.?

You can use built in functions found in Excel (if you have access to a copy) or you can go to the calc portion of open office (which is free) and derive the calculation, following the wizard's guidance to fill in the formula.

Start with this question: If the loan was interest free, how much would the monthly payment be, just to pay back those amounts in equal installments? That is easy - divide the amount owed by the number of payments. Now you have an intuitive basis to determine whether the number you are told makes sense or not. For instance, $12,000 / 72 = $166.67 / month (use the calculator to check that math).

$9,000 / 72 = $125 /month. So, you can calculate the total interest (which is not an easy calculation), add it to the principal, divide by 72, and that's your monthly payment on a 6 year loan.

For your first number, using this formula: =PMT(0.005,72,-11912.35,0,0), the answer is $197.42. Or, for your 2nd question, $168.04. Note that I used the approximate interest rate - annual interest of 6% is monthly interest of .5% or .005; also, note that I entered the borrowed amount as a negative number - because you 'took' it from someone else to pay for the car. Now you owe them the money, so it's negative. You pay with real dollars, a positive value.

One last note: as a general rule, warranties offered from a dealer increase their profit margin (but anyone who sells you a warranty will make money on it), and you have to be careful that you're not paying for this add'l warranty for the period covered by the manufacturer. You don't want to pay twice for coverage you can only use once.

You didn't mention whether you had already included sales tax, title, and registration. You also didn't mention whether you have a down payment.

Assuming you have already included the tax, title, and registration, and you are putting $0 down:

$197.36 with a warranty

$167.98 without a warranty.

Go to the site in my Sources section, and you'll be able to more accurately calculate it, including sales tax for your zip code, as well as title and registration fees, and adjust for any down payment you make.