Final answer:
To find the unpaid balance of a loan, one must use the amortization formula considering the original loan details. However, without the original monthly payment or loan details, the remaining balance cannot be calculated directly.
Step-by-step explanation:
To find the unpaid balance on a debt after 6 years of monthly payments on a $170,000 loan at 4% interest over 25 years, we can use the amortization formula. An amortization formula takes into account the principal amount, the interest rate, and the number of payments to calculate what portion of each payment goes towards the principal and interest.
Unfortunately, without the original monthly payment amount or more specific loan details, we cannot calculate the remaining balance directly. However, if the monthly payment was known as R, after making payments for 6 years (72 payments), one would need to calculate the remaining balance on the original amortization schedule to find out exactly how much is still owed. It's also possible to use an online loan calculator to input the original loan details and find the remaining balance after 72 payments.