You borrow 2 500 000 kr to buy a mountain cottage. The loan is an annuity loan with 20 payments, first payment is one year. The annual interest rate is 1.8%. a) Calculate the size of the annual payment. b) How much of the first payment is interest, and how much is down payment on loan? c) Immediately after the 5th payment the annual interest rate is increased to 2.2%. Calculate the size of the payments from now on. d) What would the size of the payment for the original loan (2 500 000 kr over 20 years at 1.8% annual interest) be if you decided to pay monthly payments rather than annual payments