Exercise 9A
Q1 | Ex-9A | Class 7 | SChand Composite Maths | Percentage and it's application | myhelper
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Question 1
Name each of fraction as percent:
(i) $\frac{3}{100}$
Sol: 3%
(ii) $\frac{29}{100}$
Sol: 29%
(iii) $\frac{151}{100}$
Sol: 151%
(iv) $\frac{12.5}{100}$
Sol: $=12.5 \%$
(v) $\frac{235}{100}$
Sol: 235%
Q2 | Ex-9A | Class 7 | SChand Composite Maths | Percentage and it's application | myhelper
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Question 2
Express each of the following as a fraction in Simplest form:
(i) $25 \%$
Sol: $\frac{25}{100}=\frac{1}{4}$
(ii) 625%
Sol: $\frac{625}{100}$
$\frac{25}{4} \Rightarrow 6 \frac{1}{4}$
(iii) $33 \frac{1}{2} \%$
Sol: $=\frac{67}{2} \%=\frac{67}{200}$
(iv) $66 \frac{2}{3} \%$
Sol: $\frac{200}{3} \%=\frac{200}{300}=\frac{2}{3}$
(v) 9.2%
Sol: $\frac{9 \cdot 2}{1000}=\frac{23}{250}$
(vi) 18.75 %
Sol: $\frac{18.75}{100}$
=$\frac{1875}{100 \times 100}$
=$\frac{3}{16}$
Q3 | Ex-9A | Class 7 | SChand Composite Maths | Percentage and it's application | myhelper
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Question 3
Convert each of the following Percent into decimal:
(i) 27%
Sol: $\frac{27}{100}=0.27$
(ii) 8%
Sol: $\frac{8}{100}=0.08$
(iii) 130%
Sol: $\frac{130}{100}=1.3$
(iv) 69%
Sol: $\frac{69.5}{100}=0.695$
(v) $3.68 \%$
Sol: $\frac{3.68}{100}=0.0368$
(vi) $0.0208 \%$
Sol: $\frac{0.0208}{100}=0.000208$
Q4 | Ex-9A | Class 7 | SChand Composite Maths | Percentage and it's application | myhelper
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Question 4
Express the following fractions as Percent:
(i) $\frac{1}{2} \times 100$
Sol: 50%
= $\frac{50}{100}=\frac{1}{2}$
(ii) $\frac{17}{25} \times 100$
Sol: 68%
(iii) $\frac{3}{8} \times 100$
Sol: $\frac{75}{2}=37.5 \%$
(iv) $2 \frac{7}{16}$
Sol: $\frac{39}{16} \times 100$
$\frac{975}{4}=243.75 \%$
(v) $\frac{14}{75}=\times 100$
Sol: $\frac{56}{3}=18 \frac{2}{3} \%$
(vi) $\frac{2}{3}$
Sol: $\frac{2}{3}\times 100 $
=$66 \frac{2}{3}$%
Q5 | Ex-9A | Class 7 | SChand Composite Maths | Percentage and it's application | myhelper
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Question 5
Convert the following decimals into percent:
(i) $0.58 \times 100$
Sol: 5.8%
(ii) $0.6 \times 100$
Sol: 60%
(iii) $0.039 \times 100$
Sol: 3.9%
(iv) 0.708 $\times 100$
Sol: 70.8%
(v) $2.05 \times 100$
Sol: = 205%
(vi) $0.001 \times 100$
Sol: 0.1%
Q6 | Ex-9A | Class 7 | SChand Composite Maths | Percentage and it's application | myhelper
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Question 6
Find the value of:
(i) $20 \%$ of 650
Sol: $\frac{26}{100} \times 650$
=130 answer
(ii) $140 \%$ of 75
Sol: $\frac{140}{100} \times 75$
$\Rightarrow 35 \times 3$
$=105 \mathrm{Ans}$
(iii) $25 \%$ of $\frac{1}{8}$
Sol: $\frac{25}{100} \times \frac{1}{8}$
$=\frac{1}{4} \times \frac{1}{8}$
$=\frac{1}{32}$
(iv) 4.5% of 60cm
Sol: $=\frac{4.5}{100 \times 10} \times 60$
$=\frac{27}{10}=2.7 \mathrm{~cm}$
(v) $7 \frac{1}{2} \%$ of $₹ 56$
Sol: $\frac{15}{2 \times 100}\times 56$
$=\frac{42}{10}=Rs 4.2$
(vi) 60% of 1 year
Sol: $\frac{60}{100} \times 365$
=219 days
Q7 | Ex-9A | Class 7 | SChand Composite Maths | Percentage and it's application | myhelper
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Question 7
What percent is :
(i) 25 of 60
Sol: $\frac{25}{60} \times 100=\frac{250}{6}=41 \frac{4}{6}$
(ii) 7.5 of 150
Sol: $\frac{7.5}{150} \times 100$
= 5% answer
(iii) 5 paise of Rs 5
Sol: $\frac{5}{500} \times 100=1 \%$
(iv) $2 \frac{1}{2} \mathrm{~cm}$ of $10 \mathrm{~cm}$
Sol: $\frac{2.5}{10} \times 100=25 \%$
(v) 55m to 1 km
Sol: 1km = 1000m
=$\frac{55}{1000} \times 100$
=5.5 %
(vi) 40 sec of 2min 40 sec
Sol: $\frac{40}{160} \times 100$
= 25%
Q8 | Ex-9A | Class 7 | SChand Composite Maths | Percentage and it's application | myhelper
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Question 8
Find the number whose:
(i) 14 % is 28
Sol: Let the number is x
=14 % of x = 28 = $\frac{14}{100} \times x=28$
= $x=28 \times \frac{100}{14}=200$ Answer
(ii) $16 \frac{2}{3} \%$ is 3
Sol: $\frac{50}{300} \times x=3 \Rightarrow x=3 \times \frac{30}{5}$
x=18 answer
Q9 | Ex-9A | Class 7 | SChand Composite Maths | Percentage and it's application | myhelper
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Question 9
What is the length whose 30 % is 24 cm ?
Sol: Let the length be x
= $30 \% of x=24 \Rightarrow \frac{30}{100} \times x=24$
=x =$24 \times \frac{100}{30}$
x= 80 answer
(ii) What is the volume of whose $16 \frac{2}{3} \%$ is 0.75 L ?
Sol:
$\frac{50}{3} \div 100 \times x=\frac{75}{100}$
$\frac{50}{3} \times \frac{1}{100} \times x=\frac{75}{100}$
$\frac{x}{6}=\frac{75}{100}$
$x=\frac{75}{100} \times 6$
$x=\frac{450}{100}=4.5$ L
Q10 | Ex-9A | Class 7 | SChand Composite Maths | Percentage and it's application | myhelper
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Question 10
What is the % change when
(i) 25 is increased to 45
Change = 45-25= 20
%Increase = $\frac{Amount increase}{Original amount}\times 100$
$\frac{20}{25} \times 100=80 \%$
(ii) 200 is decreased to 190
Decrease = 200- 190 = 10
% Decrease = $\frac{10}{200} \times 100$
=5%
(iii) 64 is increased to 144
Increase = 14 -64 = 80
% Increase = $\frac{80}{64} \times 100=\frac{1000}{8}=125 \%$
(iv) 320 is decreased to 288
Decrease = 320 - 288= 32
% Decrease = $\frac{32}{320} \times 100$
=10%
Q11 | Ex-9A | Class 7 | SChand Composite Maths | Percentage and it's application | myhelper
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Question 11
Increase
(i) Rs 80 by 5%
Sol: 5% Of 80 = Amount of increase
= $\frac{5}{100} \times 80=Rs 4$
∴ Increased amount = Original + Increase
$=80+4=Rs 84$
(ii) 440 By 80 %
Sol: Increase = 80 % of 440 = $\frac{80}{100} \times 44 0$
= 352
∴ Increase amount = 440+ 352 = Rs 792 answer
(iii) Rs 120 By $33 \frac{1}{3} \%$
Sol: Increase = $\frac{100}{3} \% of 120$
= $\frac{100}{300} \times 120$
= Rs 40
∴ Increase amount = 120 + 40 = Rs 160 Answer
(iv) 44 by 2.5 %
Sol: Increase = 2.5 % of 44 = 1.1
∴ Increase amount = 44+ 1.1= 45.1 Answer
Q12 | Ex-9A | Class 7 | SChand Composite Maths | Percentage and it's application | myhelper
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Question 12
Decrease :
(i) 400 by 25%
Decrease % = 25% of 400 = $\frac{25}{100} \times 400=100$
Total
Decrease = Original - Decrease
400- 100= 300 answer
(ii) Rs 8 by 12 %
Decrease % = 12% of 8
$=\frac{96}{100}=0.96$
Decrease amount = 8- 0.96 = Rs 7.04 answer
(iii) 150 by $33 \frac{1}{3} \%$
Sol: Decrease %= $\frac{100}{3} \% of 150=$ $\frac{100}{3 \times 100} \times 150$ =50
Decrease = 150 -50 = 100 answer
(iv) 500 by $12.5 \%$
Sol: Decrease % = 12.5% of 500
$\frac{12.5}{100} \times 500=62.5$
Decrease amount = $500-62.5$
= 437.5 answer
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