1. A family takes out a home loan for $150,000 at 6.5% monthly and plans on paying back the loan with an equal payment at the end of each month for 30 years. However, after 20 years (Immediately after the 240th payment) the loan is refinanced to 5%.

2. a) Find the original monthly payment (the monthly payment for the first 20 years).

3. b) Suppose the homeowner keeps the same loan duration after refinancing,

   Compute their monthly payment after refinancing.