You have to pay for the house via a mortgage with Westpac Bank. Assume that you take out a $400,000 loan at a fixed rate of 2.1% pa for the first three years. For the next 17 years you will be paying fixed rate of 4% per annum. Interest is compounded monthly.

How much interest will you pay to Westpac over the life of the loan (20 years)?

What if you were to pay off the loan early? 

What payment would be required if you were to pay out the loan after all the payments in the 15th year had been made?