@Jordy,
b00n's poing is valid. You need to work out your monthly repayment to the bank too. Assuming RM40k is 10% of the total value of the house, you're still looking at a monthly repayment of about ~RM2.8k [i need to double check this but i made this calculation based on interest of 7%].

For a bank to loan you the $ you need to earn roughly RM2.8k x 3 = RM8.4k. Er....damn.. my figures look like they're quite off !! *gulps* but generally that's how the calculation is like.