Mr. Lai bought an apartment three years ago. The purchase price was $5,000,000. He borrowed 60% of the purchase price through a mortgage from his bank. The interest rate of the mortgage was 6% p.a. The mortgage was to be repaid monthly for 18 years. He was not allowed to make early repayment of the principal in the first three years. After the first three years he is allowed to make any early repayment as he likes. The bank manager told Mr. Lai that the mortgage interest rate has been revised to 4.8% p.a. starting today. 1. Since Mr. Lai has an option to make early repayment of the principal to the bank now, he decides to repay $100,000 of principal today. A. Calculate the remaining period of the mortgage (in months) if Mr. Lai wants to keep the original repayment amount after repaying the $100,000 today. B. After repaying the $100,000 today, what is his new monthly payment if he wants to keep the original repayment period