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Year 8 Maths — Simple interest

Work out simple interest and the total amount, and find the rate or the time when the interest is known.

Name: ________________________

  1. 1.In a simple interest question, what does the rate tell you?

    • a) The total interest over the whole time
    • b) The interest earned on every 100 of the principal in one year
    • c) The amount borrowed at the start
    • d) The number of years the money is kept for

  2. 2.Each of these is left for 2 years. Sort them by whether the simple interest comes to less or more than $500.

    Groups: Less than $500 · More than $500

    • $4000 at 8% per year
    • $2000 at 10% per year
    • $1000 at 20% per year
    • $5000 at 8% per year
    • $5000 at 6% per year
    • $3000 at 5% per year

  3. 3.Find the simple interest on $600 at 12% per year for 5 years. Give just the number.

  4. 4.The principal and the rate stay the same, but the money is left for twice as long. What happens to the simple interest?

    • a) It stays the same
    • b) It is multiplied by itself
    • c) It halves
    • d) It doubles

  5. 5.Find the simple interest on $5000 at 8% per year for 2 years. Give just the number.

  6. 6.Find the simple interest on $2000 at 5% per year for 3 years. Give just the number.

  7. 7.The simple interest on $800 at 5% per year is $200. For how many years was the money invested?

  8. 8.In every row the principal is $1000 and the rate is 10% per year. Match each length of time to the simple interest it earns.

    • 1 year
    • 2 years
    • 3 years
    • 5 years
    • 500
    • 300
    • 100
    • 200

Answer key — Year 8 Maths — Simple interest

  1. 1. b) The interest earned on every 100 of the principal in one year
  2. 2. $2000 at 10% per year → Less than $500; $5000 at 6% per year → More than $500; $1000 at 20% per year → Less than $500; $4000 at 8% per year → More than $500; $3000 at 5% per year → Less than $500; $5000 at 8% per year → More than $500
  3. 3. 360
  4. 4. d) It doubles
  5. 5. 800
  6. 6. 300
  7. 7. 5
  8. 8. 1 year → 100; 2 years → 200; 3 years → 300; 5 years → 500