You purchased your house 6 years ago using a 30-year, $200,000 mortgage with a contractual rate of 7% that calls for monthly payments. What is your monthly payment? What is the loan balance today after making 6 years worth of monthly payments? How much equity do you have in your house if appreciation has averaged 3% per year?

I'm having trouble figuring out the second question. Why is n= 24*12?

Thank you!