A loan of $400,000 with 5% APR for 30 years with monthly payment plan was received for purchasing a new house. The home owner paid the mortgage for 10 years monthly on time. After 10 years, the home owner's request to refinance the rest of the loan for the next 20 years was approved with 4% APR. After 10 years of paying the loan with 4% APR, the home owner's request to refinance the rest of the loan for the last 10 years was approved with 3% APR. What is the mortgage for the last 10 years? ( 30 points)