Percentages & money in real life

Percentages are used everywhere in real life — discounts, tax, interest and tips. To find a percentage of an amount, convert the percentage to a decimal (divide by 100) and multiply. A discount reduces a price, so subtract the discount amount from the original price. GST (Goods and Services Tax) in Australia adds 10% to most purchase prices. Simple interest is calculated as a percentage of the original amount, added each year.

Key terms

Discount:

An amount subtracted from the original price.

GST:

Goods and Services Tax, a 10% tax added to most purchases in Australia.

Simple interest:

Interest calculated as a fixed percentage of the original amount.

Questions

1. 1. To find a percentage of an amount, you:

   • Add the percentage
   • Convert to a decimal and multiply
   • Divide by the percentage
   • Multiply by 100

2. 2. 10% of $50 is:

   • $5
   • $10
   • $15
   • $50

3. 3. 50% of $80 is:

   • $20
   • $40
   • $8
   • $60

4. 4. A discount reduces the:

   • Tax
   • Price
   • Percentage
   • GST

5. 5. In Australia, GST adds:

   • 5%
   • 10%
   • 15%
   • 20%

6. 6. 25% of $100 is:

   • $15
   • $20
   • $25
   • $30

7. 7. If something is "on sale", the price usually:

   • Increases
   • Decreases
   • Stays the same
   • Doubles

8. 8. A $60 shirt is 20% off. The discount amount is:

   • $6
   • $12
   • $20
   • $48

9. 9. A $60 shirt is 20% off. The sale price is:

   • $40
   • $48
   • $52
   • $54

10. 10. A $200 item has 10% GST added. The total price is:

    • $210
    • $220
    • $180
    • $190

11. 11. What is 15% of $40?

    • $4
    • $6
    • $8
    • $10

12. 12. A $150 jacket is discounted by 30%. The sale price is:

    • $45
    • $105
    • $120
    • $180

13. 13. What is 5% of $300?

    • $5
    • $15
    • $30
    • $50

14. 14. A $25 item has 10% GST added. What is the GST amount?

    • $2
    • $2.50
    • $5
    • $10

15. 15. A $120 item is discounted 15%, then 10% GST is added to the discounted price. What is the final price?

    • $112.20
    • $102.00
    • $120.00
    • $132.00

16. 16. You invest $500 at 4% simple interest per year. How much interest do you earn after 1 year?

    • $20
    • $4
    • $40
    • $500

17. 17. You invest $500 at 4% simple interest per year. How much interest do you earn after 3 years?

    • $60
    • $20
    • $120
    • $512

18. 18. A $80 item increases in price by 25%. What is the new price?

    • $100
    • $105
    • $20
    • $25

19. 19. An item's price drops from $50 to $40. What percentage discount is this?

    • 10%
    • 20%
    • 25%
    • 50%

20. 20. A $250 laptop is on sale for $200. What percentage was the discount?

    • 20%
    • 25%
    • 50%
    • 10%