Page 288 - ICSE Math 6

Practice Time Exercise 8.2
1. (a) M = {January, February, March, April, May, June, 1. (a) True (b) True (c) False (d) False (e) True
July, August, September, October, November, (f) False (g) True (h) False
December} 2. 18 3. 105 4. 15 5. 5
(b) D = {1, 2, 4, 5, 8, 10, 20} Exercise 8.3
(c) P ={11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47} 1. ` 90 2. 210 m 3. 63 kg 4. 96 litres 5. 21.9 g
(d) A = {E, O} (e) A = {1} 6. ` 1,440 7. 90 kg 8. ` 16,020
(f) B = {1, 10, 15, 20, 25}
2. (a) A = {x | x is an even natural number} Mental Maths
(b) X = {x | x is a season of the year} 1. (a) 6; 11 (b) 13; 2 (c) 2; 45 and 9; 10 (d) extreme
(e) 5
1
(c) B = {x | x = , n ∈ N, n < 5} 2. (a) True (b) False (c) True (d) True
n
(d) D = {x | x is one of the first six small alphabets of Practice Time
English} 1. (a) 1 : 7 (b) 1 : 2 (c) 21 : 2 (d) 12 : 55
3. B = {4, 14, 24, 34, 44}; B = {y | y = x + (–6), x ∈ A} 2. (a) 4 : 1 (b) 3 : 1 (c) 2 : 1 (d) 2 : 7 3. 3 : 7
4. (a) A = {–5, –4, –3, –2, –1, 0, 1, 2, 3, 4, 5}; n(A) = 11 4. 3 : 1 5. (a) 15 (b) 28 6. ` 14,000
(b) X = {1, 4, 9, 16}; n(X) = 4 7. 50; 100: 150 8. ` 100; ` 300 9. 99; 132
(c) B = {X, M, P, L}; n(B) = 4 10. (a) 33 (b) 35 11. 15 12. 36 13. 9 kg
(d) D = {2, 3, 5, 7}; n(D) = 4 14. 700 minutes 15. 10 litres 16. ` 1,15,000 17. Rahul
(e) S = {1, 3, 5, 7, 9, 11, 13}; n(S) = 7
5. (a) A = {5, 10, 15, 20, 25,...} Think Smart
(b) B = {1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, 60} 1. Moksh as 3 parts > 2 parts. st
(c) X = {–4, –3, –2, –1, 0, 1, 2} 2. No, as new ratio = (original 1 quantity + 1) : (original
nd
2 quantity + 1)
(d) Y = {3, 5, 7, 11,...} 3. Yes
(e) P = {B, E, A, U, T, I, F, L}
(f) Q = {S, W, E, T} Chapter 9
6. (a) This method can be selected as we can separate students Exercise 9.1
according to their roll numbers. 1. (a) 75 (b) 10 (c) 23 (d) 100
2
(b) This method cannot be selected as there is no standard 2. (a) 40% (b) 28% (c) 16 % (d) 1.8%
3
to decide someone’s intelligence. 1 2
7
11
(c) This method can be selected as we can separate students 3. 9 % 4. 64 %
according to their names. 5. 2,250 6. ` 8,400 7. 900 8. 1,800
7. (a) 35 (b) 5 9. 540
Think Smart Exercise 9.2
2
1. Yes; If set A contains all the elements of finite sets B and 1. 10,500 2. 40% 3. 40 kg 4. 60 5. 4 %
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C, then n(A) = n(B) + n(C). Mental Maths
2. 1 3. February 1. (a) False (b) True (c) True (d) False

Chapter 8 2. (a) 50 (b) 200 (c) 50
Exercise 8.1 Practice Time
1
2
1
1. (a) 3; 7 (b) 13; 21 (c) 17 : 23 (d) 12 : 97 1. (a) 33 % (b) 16 % (c) 11 % (d) 20%
3
9
3
2. (a) 10 : 9 (b) 3 : 11 (c) 13 : 4 (d) 35 : 2 2. 20% 3. (a) 200 (b) ` 1,250 (c) 66 (d) 587.5 kg
3. (a) 12 : 5 (b) 3 : 2 (c) 5 : 3 (d) 12 : 49 4. 175 5. 450 6. 792
4. 1 : 3 5. 2 : 1; 1 : 2 6. (a) 24 (b) 45 7. 24 years 7. (a) English: 68.75%; Mathematics: 82%; Science: 85%
8. 30; 45 9. ` 900; ` 1,100 10. 80 cm; 140 cm; 180 cm (b) 80 16 %
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11. 18°; 126°; 36° 12. 180 cm 8. 1,280 or more 9. 182.75 cm
13. (a) 5 : 8 < 7 : 9 (b) 11 : 15 < 13 : 14
(c) 7 : 18 = 11 : 36 (d) 16 : 19 < 21 : 23 Think Smart 1
(e) 15 : 32 < 9 : 17 (f) 8 : 15 > 7 : 16 1. 25% 2. 84 3. Yes, as 50% = 4. 40% 5. 3,280 words
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