6th Maths : Term 1 Unit 3
Ratio and Proportion | Exercise 3.1(i) Ratio of ₹ 3 to ₹ 5 = 3 : 5.
(ii) Ratio of 3m to 200 cm = 3 : 2. [Note: 200cm = 2m]
(iii) Ratio of 5 km 400 m to 6 km = 9 : 10. [Note: 54:60]
(iv) Ratio of 75 paise to ₹ 2 = 3 : 8. [Note: 75 : 200]
(i) The ratio of 130 cm to 1 m is 13 : 10. [True]
(ii) One of the terms in a ratio cannot be 1. [False]
(i) 15 : 20 (ii) 32 : 24 (iii) 7 : 15 (iv) 12 : 27 (v) 75 : 100
(i) 15 : 20
Fractional form = \( \frac{15 \div 5}{20 \div 5} = \frac{3}{4} \)
Simplest form = 3 : 4
(ii) 32 : 24
Fractional form = \( \frac{32 \div 8}{24 \div 8} = \frac{4}{3} \)
Simplest form = 4 : 3
(iii) 7 : 15
Fractional form = \( \frac{7}{15} \) (No common divisor)
Simplest form = 7 : 15
(iv) 12 : 27
Fractional form = \( \frac{12 \div 3}{27 \div 3} = \frac{4}{9} \)
Simplest form = 4 : 9
(v) 75 : 100
Fractional form = \( \frac{75 \div 25}{100 \div 25} = \frac{3}{4} \)
Simplest form = 3 : 4
Distance Akilan walks in an hour = 10 km
Distance Selvi walks in an hour = 6 km
Ratio of distance covered by both = 10 : 6
Simplest form: \( \frac{10 \div 2}{6 \div 2} = \frac{5}{3} \)
Ratio of distance covered by Akilan and Selvi = 5 : 3
Parking cost of a bicycle = ₹ 5
Parking cost of a scooter = ₹ 15
Simplest ratio of bicycle to scooter: \( \frac{5 \div 5}{15 \div 5} = \frac{1}{3} \)
Ratio of bicycle parking cost to scooter parking cost = 1 : 3
(i) number of boys to the number of girls.
(ii) number of girls to the total number of students.
(iii) number of boys to the total number of students.
Total No. of students = 50
No. of boys = 30
No. of girls = 50 − 30 = 20 girls
(i) number of boys to the number of girls:
boys : girls = 30 : 20
Simplest form = \( \frac{30 \div 10}{20 \div 10} = \frac{3}{2} \)
Ratio = 3 : 2
(ii) number of girls to the total number of students:
girls : total students = 20 : 50
Simplest form = \( \frac{20 \div 10}{50 \div 10} = \frac{2}{5} \)
Ratio = 2 : 5
(iii) number of boys to the total number of students:
boys : total students = 30 : 50
Simplest form = \( \frac{30 \div 10}{50 \div 10} = \frac{3}{5} \)
Ratio = 3 : 5
Objective Type Questions
7. The ratio of ₹ 1 to 20 paise is __________.
Answer: (d) 5 : 1
8. The ratio of 1 m to 50 cm is __________.
Answer: (c) 2 : 1
9. The length and breadth of a window are 1m and 70 cm respectively. The ratio of the length to the breadth is __________.
Answer: (d) 10 : 7
10. The ratio of the number of sides of a triangle to the number of sides of a rectangle is:
Answer: (b) 3 : 4
11. If Azhagan is 50 years old and his son is 10 years old, then the simplest ratio between the age of Azhagan to his son is:
Answer: (c) 5 : 1
Quick Answers Summary:
1) (i) 3:5, (ii) 3:2, (iii) 9:10, (iv) 3:8
2) (i) True, (ii) False
3) (i) 3:4, (ii) 4:3, (iii) 7:15, (iv) 4:9, (v) 3:4
4) 5 : 3
5) 1 : 3
6) (i) 3:2, (ii) 2:5, (iii) 3:5
7) (d) 5:1 | 8) (c) 2:1 | 9) (d) 10:7 | 10) (b) 3:4 | 11) (c) 5:1