S_Loan(cont'd)

So here is where the math gets interesting. To find the number of payments I would
have to make to pay off a 120$ at 5% interest calculated monthly, with 10$ monthly
payments, I would need to use the following formula:

PMT = 10; PV = 120; i = .004167 (which is .05/12)

The answer I get is a fraction above 12, with rounding 13. We are in the labyrinth
of financial mathematics.

Seriously, if using natural logarithms seems odd for financial calculations, ratios of ln values
can be handy indeed.

http://www.calculatorsoup.com/calculators/financial/loan-calculator.php