Use the formula for the present value of an ordinary annuity or the amortization formula to solve the following problem.
PV=12000
i-=0.01
PMT=300
n=???
Please post the complete problem. As it is there is not enough information, as you have not told us how many times the interest compounds in a year.
Am I correct in assuming that "i" is the annual interest rate?
Well then it can not be solved. You need to know how many times the interest compounds in a year, so that you can calculate the necessary interest rate and the number of times the interest compounds in total.