Page 309 - ICSE Math 7

1 1 1 Think Smart
6. (a) 20%, 30%, 50% (b) 12 %, 31 %, 56 %
2 4 4 1. ` 22,000 2. ` 4,720
(c) 20%, 32%, 48% (d) 10%, 20%, 70% 3. (a) On increasing marked price of an article its selling
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7. (a) 10% (b) 20% (c) 5% (d) 8 % price will also increase. So the profit will increase.
1 3 (b) On increasing discount on an article its selling price
8. 10% 9. 1 % 10. 15 11. 6,375 kg 12. 800 13. 396
3 will decrease. So, the profit will decrease.
Exercise 8.2 (c) On decreasing the selling price of an article, its profit
1 will decrease.
1. 10% 2. 5% 3. 8 % 4. ` 966 5. 1,250
1 3 1
6. 12.5% 7. 6 % 8. 140 cm 9. 4% 10. 23 % Chapter 10
3 13
Mental Maths Exercise
1. (a) False (b) True (c) True (d) False (e) True 1. (a) ` 45; ` 295 (b) ` 198; ` 1,098
(f) True 2. (a) ` 15 (b) 40 kg (c) 200 (d) 50 (c) ` 252; ` 2,052 (d) ` 48; ` 848
2. ` 8,000 3. ` 8,000 4. 9 years 5. 3 years 6. 1.5%
Practice Time 7. 10 years 8. ` 7,000
1. ` 94,394 2. 164.3 cm 3. 420 4. 82,080 5. 340
2 Mental Maths
6. 7% 7. 16 % 8. ` 1,500 9. English
3 Principal (in `) Interest (in `) Amount (in `)
10. Wife–` 32,000, Elder daughter–` 28,800, 1.
Younger daughter–` 19,200 11. ` 20,000 900 90 990
12. ` 65,000 13. 70% 14. 1 kg; 0.8 kg 15. 30,000 1,000 250 1,250
2,400 2,400 4,800
Think Smart 650 150 800
1. 2% increased 2. Males : 32%; Females : 48% 3,590 90 3,680
3. 2,16,000 votes
2. (a) principal (b) interest; amount (c) months (d) 20%
Chapter 9
Practice Time
Exercise 9.1 1
2 1. ` 850 2. 5 % 3. 12 years
2
1. (a) Profit% = 6.25% (b) Loss% = 22 % 1
9
2 4. 3 % 5. ` 422.40 6. ` 1,600; 5%
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(c) Loss% = 14 % (d) Profit% = 9% 7. ` 750 8. 5 years 9. ` 1,444 10. 5 years
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2
2. ` 3,200 3. Profit = 66 % Think Smart
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5
4. Loss% = 20 % 5. ` 38 6. ` 37,800 1. ` 15,000 2. ` 4,000
6
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7. ` 1,21,900 8. 50% 9. Loss% = 8 % Chapter 11
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10. ` 28,000 11. Loss% = 4%
Exercise 11.1
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Exercise 9.2 1. 80 km h 2. 2 h 3. (a) 990 km h (b) h
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1. ` 22,500 2. ` 25, 20% 3. 10% 4. ` 11,400 3 2 4
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5. (a) ` 6,720 (b) ` 672 (c) ` 6,048 (d) Profit–8% 4. (a) 7 h (b) 51 km h 5. (a) 142 km (b) 40 km h –1
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7
2
6. 14% 7. (a) ` 3 (b) 6% 8. Profit = 4.5% 6. (a) 87.6 km h (b) 61 km h 7. 2,700 km 8. 4.2 km
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Mental Maths Exercise 11.2
1. (a) True (b) False (c) False (d) True 1. 1 min 40 s; 150 m 2. (a) 3 km (b) 22.5 km
2. (a) ` 750 (b) cost price (c) listed (d) discount 3. (a) 72 km h (b) 9.5 s (c) 19 s
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Practice Time 4. (a) 4.5 h (b) 3.25 h 5. 2.4 km h 6. 630 km
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1. 12 % 2. Profit% = 20% 3. ` 7 4. ` 9,450 Mental Maths
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5. Profit% = 100% 6. 50% 7. Loss% = 40 20 % 1. (a) True (b) True (c) False (d) False
31
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8. ` 651 9. 24% 10. ` 25,000 11. 12% 2. (a) 840 km h (b) 22 s (c) 6 km h (d) 450 m
12. (a) ` 8,125 (b) ` 812.50 (c) ` 7,312.50 (d) 12.5% Practice Time
13. 62.5% 1. (a) 3.4 km (b) 22.2 km 2. (a) 28 s (b) 48 s
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