A family plans to buy a new house in the next three years from now for 4,000,000 Baht by applying for a 25-years mortgage loan at the time of purchase. However, banks generally will lend the amount of money at the 40% of the gross family income. The family expects that their gross income will be 40,000 Baht per month at the time they buy a house. So, the mortgage loan will not provide enough money to buy a house and the family will need to have a down payment to make up the difference. If the family has already saved 100,000 Baht in the bank account with 6% pa quarterly compounding return, how much money do they need to deposit each month so that they have enough money for a down payment? Assume that the borrowing rate is 7.5% pa and 1-month time deposit is 6%pa