Alex Karez has taken out a loan of $180,000 with an annual rate of 10% compounded monthly to pay off hospital bills from his wife's illness. If the most Alex can afford to pay is $3,500 a month, how long will it take to pay off the loan? How long will it take to pay off the loan if he can pay $4,000 each month? Use five decimal places for the monthly percentage rate in your calculations. If Alex can pay $3,500 a month, how many years will it take to pay off the loan?

Please show your work on how you got your answer.