Final answer:
The new monthly payment after refinancing is $1,366.
Step-by-step explanation:
To find the new monthly payment after refinancing, we first need to calculate the remaining loan amount after 5 years. Since the down payment was 25%, the initial loan amount is 75% of $325,000, which is $243,750. After 5 years, we need to calculate the loan balance using the formula:
Loan Balance = Initial Loan Amount * (1 + Monthly Interest Rate)^(Number of Payments)
Where the Monthly Interest Rate is (Annual Interest Rate / 12) and the Number of Payments is (Number of Years * 12). The monthly interest rate after refinancing is 5.1% / 12 = 0.425% and the number of payments is (25 * 12) = 300. Plugging these values into the formula:
Loan Balance = $243,750 * (1 + 0.00425)^300 = $198,915.51
Finally, we can calculate the new monthly payment using the formula for a fixed-rate mortgage:
New Monthly Payment = (Loan Balance * Monthly Interest Rate) / (1 - (1 + Monthly Interest Rate)^(-Number of Payments))
Plugging in the values:
New Monthly Payment = ($198,915.51 * 0.00425) / (1 - (1 + 0.00425)^(-300)) = $1,366
Therefore, the new monthly payment after refinancing is $1,366.