A mortgage borrower has an outstanding debt at interest rate of J12= 10% and 150 USD monthly payments for 69 months remaining today. Another bank is offering the same monthly payments but for 63 months only at a lower interest rate. For the refinancing, borrower has to pay 450 USD expense today. Decide if the borrower should refinance the debt or not by showing the difference of discounted values of two alternatives.

must use the same interest rate for discounting two options to be able to compare

please show formulas and steps... not computer formulation