Mr Wickham borrowed $425,800 from the bank to buy a house. The interest rate was 6.258% p.a. compounded semi-annually and the mortgage contract specified that the loan was to be paid back with equal monthly payments over 25 years with the first payment exactly one month after taking out the loan. Mr Wickham has just made the 124th payment.

a. What was the principal portion of the payment that he just made?

b. Mr Wickham knows that in the early stages of the loan most of the payment consists of interest and very little consists of principal. He also knows that as time passes, the interest portion gets less and less while the principal portion of the payment gets more and more. At what payment does the interest portion first drop to less than half the payment?

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