4 ESO Academics - Unit 01 - Exercises 1.4. Percentages. Simple Interest and Compound Interest

1. UNIT 01 September
1. Calculate.
a) 𝟓𝟓% 𝐨𝐨𝐟𝐟 𝟏𝟏, 𝟎𝟎𝟎𝟎𝟎𝟎 b) 𝟏𝟏𝟏𝟏𝟏𝟏% 𝐨𝐨𝐟𝐟 𝟕𝟕𝟓𝟓𝟓𝟓
c) 𝟑𝟑𝟖𝟖% 𝐨𝐨𝐟𝐟 𝟖𝟖𝟎𝟎𝟎𝟎 d) 𝟎𝟎, 𝟔𝟔% 𝐨𝐨𝐟𝐟 𝟏𝟏, 𝟒𝟒𝟒𝟒𝟒𝟒
e) 𝟏𝟏𝟐𝟐, 𝟑𝟑% 𝐨𝐨𝐟𝐟 𝟓𝟓𝟓𝟓𝟓𝟓 f) 𝟖𝟖𝟖𝟖% 𝐨𝐨𝐟𝐟 𝟔𝟔𝟒𝟒𝟒𝟒
g) 𝟏𝟏𝟐𝟐𝟐𝟐% 𝐨𝐨𝐟𝐟 𝟑𝟑𝟑𝟑𝟑𝟑 h) 𝟒𝟒𝟑𝟑% 𝐨𝐨𝐟𝐟 𝟓𝟓𝟐𝟐𝟐𝟐
2. Calculate the percentage increase or the percentage decrease:
a) 10 to 12.
b) 12 to 10.
c) 80 to 60.
d) 60 to 80.
3. Find the 12% of the 115% of 1,575.
4. After increasing an amount 12%, we calculated its 20% and we get 12. Calculate the
amount.
Axel Cotón Gutiérrez Mathematics 4º ESO Exercises 4.1.4.1

2. UNIT 01 September
5. Mary bought a car that cost 18,000 €, she had a discount of 20%. We had to add the
21% VAT. How much she paid?
6. Which one is the profit generated by these amounts at a with 3% simple interest:
a) 2,000 € during 5 years
b) 30 € during 7 years
c) 4,500 € during 8 months
d) 670 € during 30 months
7. Calculate the Principal that generates 490 € in 5 years at a 3.6% simple interest.
Axel Cotón Gutiérrez Mathematics 4º ESO Exercises 4.1.4.2

3. UNIT 01 September
8. Find out the interest rate when 20,000 € is invested for 3 years at a 5% simple interest
that generates 2,400 € profit.
9. Find the final amount for the following principals invested at 3.4% annual compound
interest:
a) 600 € during 5 years
b) 3,400 € during 2 years
c) 5,400 € during 3 years
d) 40,000 € during 2 years
Axel Cotón Gutiérrez Mathematics 4º ESO Exercises 4.1.4.3

4. UNIT 01 September
10. Ann invest 1,000 € at 2% annual compound interest during 5 years. Mark does the
same but at simple interest. What is the profit of each one? Which one is bigger?
11. A principal is invested during 3 years at 5% annual compound interest. If the profit is
1,576.25 €, which is the principal?
Axel Cotón Gutiérrez Mathematics 4º ESO Exercises 4.1.4.4

5. UNIT 01 September
http://www.mathgames.com/skill/7.58-compound-interest
http://www.mathgames.com/skill/7.62-simple-interest
Axel Cotón Gutiérrez Mathematics 4º ESO Exercises 4.1.4.5

6. UNIT 01 September
http://www.mathgames.com/skill/7.63-percent-of-a-number-tax-discount-tip
Axel Cotón Gutiérrez Mathematics 4º ESO Exercises 4.1.4.6