YEARS: 7–8, 9–10
When we need to buy a house we usually have to take out a loan from the bank.
We have to pay back that loan with interest. A $350,000 loan can mean paying back $869,000!
Listen to Nathan Bazley explain why a small change in interest rates can mean a big difference to the total amount you repay.
This clip provides a context for simple and compound interest rates.
Things to think about
- 1.Do a quick internet search to find out the average price of a house and the average home loan in your state. How does a bank loan help someone buy a house?
- 2.The reporter uses a house worth $350,000 and says by the time you've paid it off, the total could come to around $869,000. What would cause this large increase? Customers were complaining about an increase in interest rates. How would this affect their repayments? If the average price of a house is $350,000, and you borrowed 90% of the money, this would mean a loan of 0.90 x 350,000 = $315,000. If the loan was for 15 years, at an interest rate of 7% pa compounding annually, and you did not pay back anything until 15 years was up, you would owe: 315,000 x (1 + 7/100)^15 = $869,094. Calculate what you would owe if the loan was for 20, 25 or 30 years.
- 3.A $315,000 loan taken for 15 years at a rate of 7% pa compounding annually would mean you would have to pay back: 315,000 x (1 + 7/100)^15 = $869,905 in total. Calculate the total amount to be paid back if the banks increased the rate to 7.25% pa or 7.5% pa. Comparing your result to the total for 7%, work out the difference in the totals and divide this difference by 15 x 12 (15 years by 12 months) to work out how much extra you will have to pay back each month. The answers are included in the following: $189.65, $345.20, $167.50, $386.20.
- 4.Repayments are actually calculated so that a small amount of the principal is paid off each month. This reduces the principal and pays the interest owing for that month.
Date of broadcast: 16 Nov 2010
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