Page 98 - New Medley 5 Semester 2

Example 2: Write any two ratios equivalent to each of the following.

(a) 3 : 7 (b) 15 : 27 (c) 16 : 20

3 3 × 2 6
Solution: (a) 3 : 7 = = = = 6 : 14
7 7 × 2 14

3 3 × 3 9
and = = = 9 : 21
7 7 × 3 21

 6 : 14 and 9 : 21 are equivalent to 3 : 7.

15 15 ÷ 3 5
(b) 15 : 27 = = = = 5 : 9
27 27 ÷ 3 9

5 5 5 × 2 10
and = = = = 10 : 18
9 9 9 × 2 18

 5 : 9 and 10 : 18 are equivalent to 15 : 27.

16 16 ÷ 2 8
(c) 16 : 20 = = = = 8 : 10
20 20 ÷ 2 10

16 16 ÷ 4 4
and = = = 4 : 5
20 20 ÷ 4 5

 8 : 10 and 4 : 5 are equivalent to 16 : 20.

Example 3: Out of 42 students, 28 are boys in a section of Class 5.
Find the ratio of:

(a) boys to girls

(b) girls to the total students

(c) boys to the total students.

Solution: Total number of students = 42, number of boys = 28

 Number of girls = 42 – 28 = 14

28 2
(a) Ratio of boys to girls = 28 : 14 = = = 2 : 1
14 1

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