Am i able to get a full explanation of this to include the actual formular?

Question 1

Now that she has accumulated a deposit of $100,000, Julie wishes to use this deposit and take out a housing loan to purchase a home. The home costs $600,000. The loan is to be repaid in equal monthly instalments over a term of 25 years.Julie recalls that the interest rate quoted by the bank is an annual nominal rate of 3.6%pa compounded monthly.After 5 years (60th repayment just about to be made), the bank announces the interest rate will change to an annual nominal rate of 2.8%pa compounded monthly.

(i) How much is the original monthly repayment?

(ii) How much is the owed at the time of the interest rate fall?

(iii) Assuming the new repayments are calculated after the 60th repayment has been made, provide Julie with a repayment schedule using excel.

(Answers should be accurate to the nearest dollar)