Hello, I need help answering this review question:

Problem 3

Five years ago, you purchase a house of $500,000. You borrow a mortgage with 80% of LTV (loan to value ratio). The interest rate on the mortgage is 5%.Payment terms are being mademonthlyto amortize the loan over 30 years. You have found another lender who will refinance the current outstanding loan balance at 4.0% with monthly payments for 30 years. The new lender will charge two discount points on the new loan.Other refinancing costs will equal $2,000.

Questions

1. What is your monthly payment for the current loan?
2. What is the new loan amount if you choose to refinance?
3. What is your monthly payment for the new loan?
4. What is the effective cost of your new loan if you hold the loan for 30 years?
5. If you want to refinance today, at least how many years should you stay in the house (do not prepay)? Why?