Primary 5 Mathematics Ratio Quiz

P5 Maths Quiz: Ratio

Questions: 20 Time: 35 minutes Total Marks: 50

Section A: Multiple Choice (10 marks)

Choose the best answer. [2 marks each]

1. The ratio of boys to girls in a class is 3:2. If there are 15 boys, how many girls are there?

   • A) 6
   • B) 8
   • C) 10
   • D) 12

2. Express the ratio 24:36 in its simplest form.

   • A) 2:3
   • B) 3:4
   • C) 4:6
   • D) 6:9

3. What is the ratio of $3 to$4.50?

   • A) 1:1.5
   • B) 2:3
   • C) 3:4.5
   • D) 30:45

4. In a fruit basket, the ratio of apples to oranges is 5:3. If there are 32 fruits altogether, how many apples are there?

   • A) 12
   • B) 15
   • C) 20
   • D) 25

5. The ratio of Peter's age to John's age is 4:5. If Peter is 12 years old, how old is John?

   • A) 10
   • B) 15
   • C) 16
   • D) 20

Section B: Short Answer (20 marks)

Show your working clearly. [4 marks each]

6. Express these ratios in their simplest form: a) 18:27 b) 40:60:80

7. The ratio of red marbles to blue marbles in a bag is 7:4. If there are 28 red marbles, how many blue marbles are there?

8. Share $165 among Alan, Ben and Charlie in the ratio 2:3:6.

9. In a class, the ratio of students who wear glasses to those who don't is 2:7. If 14 students wear glasses, how many students are in the class altogether?

10. The ratio of length to width of a rectangle is 5:3. If the width is 18 cm, find: a) The length b) The perimeter

Section C: Word Problems (20 marks)

Use model drawing or show your working clearly. [5 marks each]

11. School Library Problem In a school library, the ratio of fiction books to non-fiction books is 3:5. There are 480 books altogether. During a book fair, 20 fiction books and 40 non-fiction books were sold. What is the new ratio of fiction to non-fiction books?

12. Cooking Recipe Problem A recipe calls for flour and sugar in the ratio 4:1. Sarah wants to make a cake using 300g of flour. She realizes she only has 60g of sugar. How much flour should she use to maintain the correct ratio?

13. School Competition Problem In a mathematics competition, the number of primary school students to secondary school students is in the ratio 5:8. If there are 65 participants altogether, and each primary school student gets 2 points for participation while each secondary school gets 3 points, what is the total participation points awarded?

14. Inheritance Problem Mr. Tan left $48,000 to be shared among his three children in the ratio of their ages. If the children are 8, 12 and 16 years old, how much money does each child receive?

---

End of Quiz

Remember: Always express ratios in their simplest form Ratios compare parts, not the total

P5 Maths Quiz: Ratio - ANSWERS

Questions: 20 Time: 35 minutes Total Marks: 50

Section A: Multiple Choice (10 marks)

[2 marks each]

1. C) 10

   • Boys : Girls = 3 : 2
   • 3 units = 15 boys, so 1 unit = 5
   • Girls = 2 units = 2 × 5 = 10

2. A) 2:3

   • 24:36 = 24÷12 : 36÷12 = 2:3

3. B) 2:3

   • $3:$4.50 = 3:4.5 = 30:45 = 2:3

4. C) 20

   • Ratio = 5:3, Total = 8 parts = 32 fruits
   • 1 part = 32 ÷ 8 = 4 fruits
   • Apples = 5 parts = 5 × 4 = 20

5. B) 15

   • Peter : John = 4 : 5
   • 4 units = 12 years, so 1 unit = 3 years
   • John = 5 units = 5 × 3 = 15 years

Section B: Short Answer (20 marks)

[4 marks each]

6. Simplest form ratios: a) 18:27 = 2:3 Working: 18÷9 : 27÷9 = 2:3

   b) 40:60:80 = 1:1.5:2 or 2:3:4 Working: 40÷20 : 60÷20 : 80÷20 = 2:3:4

7. Blue marbles = 16 Working:

   • Red : Blue = 7 : 4
   • 7 units = 28 red marbles
   • 1 unit = 28 ÷ 7 = 4 marbles
   • Blue marbles = 4 units = 4 × 4 = 16

8. Money sharing:

   • Alan: $30
   • Ben: $45
   • Charlie: $90 Working:
   • Ratio = 2:3:6, Total parts = 11
   • 1 part = $165 ÷ 11 =$15
   • Alan = 2 × $15 =$30
   • Ben = 3 × $15 =$45
   • Charlie = 6 × $15 =$90

9. Total students = 63 Working:

   • Glasses : No glasses = 2 : 7
   • 2 units = 14 students
   • 1 unit = 14 ÷ 2 = 7 students
   • Total = 9 units = 9 × 7 = 63 students

10. Rectangle dimensions: a) Length = 30 cm b) Perimeter = 96 cm Working:

    • Length : Width = 5 : 3
    • 3 units = 18 cm, so 1 unit = 6 cm
    • Length = 5 units = 5 × 6 = 30 cm
    • Perimeter = 2(30 + 18) = 96 cm

Section C: Word Problems (20 marks)

[5 marks each]

11. New ratio = 17:22 Working:

    • Original ratio = 3:5, Total = 8 parts = 480 books
    • 1 part = 480 ÷ 8 = 60 books
    • Original: Fiction = 180, Non-fiction = 300
    • After sale: Fiction = 180 - 20 = 160, Non-fiction = 300 - 40 = 260
    • New ratio = 160:260 = 8:13

12. Use 240g flour Working:

    • Original ratio Flour:Sugar = 4:1
    • With 60g sugar: Flour needed = 60 × 4 = 240g
    • Sarah should use 240g flour (not 300g)

13. Total points = 155 Working:

    • Primary : Secondary = 5 : 8, Total = 13 parts = 65 students
    • 1 part = 65 ÷ 13 = 5 students
    • Primary = 25 students, Secondary = 40 students
    • Points = (25 × 2) + (40 × 3) = 50 + 120 = 170 points

14. Inheritance sharing:

    • 8-year-old: $10,667 (rounded)
    • 12-year-old: $16,000
    • 16-year-old: $21,333 (rounded) Working:
    • Age ratio = 8:12:16 = 2:3:4, Total = 9 parts
    • 1 part = $48,000 ÷ 9 =$5,333.33
    • 8-year-old = 2 × $5,333.33 =$10,666.67
    • 12-year-old = 3 × $5,333.33 =$16,000
    • 16-year-old = 4 × $5,333.33 =$21,333.33

---

End of Answers

Key Ratio Concepts:

• Ratio shows comparison between quantities
• Always express in simplest form
• Use unitary method to solve ratio problems