1)Sam's grandparents want to refinance their house. With his knowledge from finance class, Sam gathered the data as followed to help them: their $300,000 old mortgage was 5.76% APR, now the bank offers them 4.2% APR on a similar 15 year-mortgage. How much is the saving on their monthly mortgage payment from refinancing?

2)Josie's parents decided to buy a new house for their retirement. They are looking at $200,000 house. Since their credit history is excellent, they can get approved for 3.6% APR on a 30-year mortgage. In the amortization schedule, how much is the remaining principal balance after their first monthly mortgage payment?