Page 308 - ICSE Math 7

5. (a) 1 (b) 2 (c) 8 (d) 32 7. 3 : 4 8. (a) 1,500; 1,200 (b) 300; 600; 1,800
6. (a) X = {1, 2, 3, 4, 5, 6} (b) X = {0, 1, 2, 3, 4, 5, 6} 9. 100 and 120 chocolates 10. 360
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(c) {..., –2, –1, 0, 1, 2, 3, 4, 5, 6} 11. (a) 6 : 7 (b) 3 : (c) 1 : 1 1
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Exercise 6.3 12. A–` 1,800; B–` 600; C–` 1,200
1. (a) A ∪ B = {2, 3, 5, 6, 7, 9}; A ∩ B = {3} Exercise 7.2
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(b) C ∪ D = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 16, 18}; 1. (a) 1 (b) 330 kg (c) 20 (d) 2.5 (e) 85 kg (f) 26
C ∩ D = {2, 4, 6, 8} 1 7 1
(c) E ∪ F = {p, q, r, s, t, v}; E ∩ F = {p, s, t} 2. (a) 10 (b) m (c) 4 (d) 1 (e) 4
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3. (a) X ∩ Y = f (b) Y ∩ V = {x : x is a prime number > 2} 3. (a) 5 : 2 = 10 : 4, 5 : 10 = 2 : 4, 10 : 5 = 4 : 2, 10 : 4 = 5 : 2
(c) Y ∩ Z = {x : x is an odd natural number} (b) 0.4 : 1.4 = 0.2 : 0.7, 0.4 : 0.2 = 1.4 : 0.7,
(d) X ∩ V = {2} (e) Z ∩ V = {x : x is a prime number} 1.4 : 0.4 = 0.7 : 0.2, 1.4 : 0.7 = 0.4 : 0.2
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(f) {x : x is a prime number} (c) : 22 = 3 : , : 3 = 22 : , : = : 3 ,
4. (a) {5, 15, 25 } (b) {4} (c) {8, 12, 14, 16, 24} 2 15 11 5 2 11 15 5 15 2 5 11
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(d) {10, 30, 40} (e) {5, 15, 25} (f) {4, 8, 12, 16, 64} 22 : = : 3 4. (a) 5. (a) 6 (b) 18 (c) 1.5
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5. 5 6. 5 1 27 5
(d) 6. (a) ` 125 (b) 0.9 (c) m (d)
Mental Maths 7 128 16
1. (a) False (b) False (c) True (d) False (e) True Exercise 7.3
(f) False 2. (a) True (b) True (c) False 1. 96 litres 2. 21.9 g 3. 50 students 4. 69 days
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(d) True (e) True 3. (a) ∈ (b) ∉ (c) ∉ (d) ∈ 5. 42 km h 6. 9 students 7. 375 soldiers 8. 42 boxes
9. ` 27,000
Practice Time
1. (a) X = {A, U}; Exercise 7.4
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X = {x | x is a vowel in the word NATURAL} 1. 6 hours 2. 100 minutes 3. 36 hours
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(b) Y = {6, 8, 10, 12}; Y = {x | x = 2n, n ∈ N, 3 ≤ n ≤ 6} 4. (a) (b) (c) 10 hours 5. 42 hours
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(c) A = {11, 13, 15, 17, 19}; 3 3
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A = {x | x = 2n – 1, n ∈ N, 6 ≤ n ≤ 10} 6. 2 days 7. 1 hours 8. 5 hours
3. (a) 7 (b) 0 (c) 5 (d) 1 (e) 7 2 5 7
4. (a) Overlapping (b) Overlapping (c) Overlapping Mental Maths
(d) Disjoint (e) Disjoint 5. (a) Equivalent 1. (a) (ii) (b) (iii) (c) (iv) (d) (i)
(b) Equal (c) Equal (d) Equivalent 2. (a) True (b) True (c) False (d) True (e) False
6. (a) X = {1, 2, 3} (b) X = {0, 1, 2, 3} 3. (a) 5 (b) 4 (c) 6 (d) 3,200
(c) X = {..., –2, –1, 0, 1, 2, 3} 7. (a) 15 (b) 0 (c) 1 Practice Time
8. {f}, {5}, {15}, {25}, {5, 15}, {15, 25}, {5, 25}, {5, 15, 25} 1. (a) 17 : 7 2. 72 cm 3. 120 candies; 40 candies
9. 8 10. {Nishant, Gitika, Naman, Pooja} 4. 30 : 23 5. 190 kg; 75 kg; 105 kg
11. (a) 19 (b) 33 12. 375; 475 6. 296; 407 7. 99; 108 8. 1
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Think Smart 9. 9 kg 10. 585 minutes 11. 69 students 12. 10 51
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1. X = 1, , , , , , , , , , 1 , 1 ; n(X) = 12 13. 2 hours 14. 3 hours 15. 12 h per day
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2. (a) {6, 18, 24, 30, 36, 42} (b) {6, 30, 24, 36, 42} Think Smart
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(c) {6, 30, 42} (d) {18} 1. 8 months 2. (a) 1 days (b) 18 days
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Chapter 8
Chapter 7
Exercise 8.1
Exercise 7.1
1. (a) 11 : 5 (b) 6 : 11 2. 9 : 1 1. (a) 12.8% (b) 0.9% (c) 75% (d) 52% (e) 85%
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3. (a) 1 : 3 (b) 5 : 7 (c) 2 : 1 (d) 1 : 5 (e) 3 : 5 2. (a) 50 (b) (c) 25 (d) 50 (e) 25
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(f) 1 : 4 (g) 6 : 5 (h) 16 : 21 3. (a) 0.13 (b) 0.345 (c) 0.69 (d) 0.069 (e) 0.08
4. (a) 6 : 25 (b) 14 : 18 (7 : 9) (c) 20 : 9 4. (a) 1 : 2 (b) 2 : 1 (c) 1 : 6 (d) 13 : 80
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(d) 27 : 14 (e) 3 : 8 5. 6. 7,500 5. (a) 16% (b) 83 % (c) 4% (d) 140%
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