myhelper: S.chand publication New Learning Composite mathematics solution of class 8 Chapter 8 Percentage and Its Application Exercise 8A

Exercise 8A

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Question 1

Find:

(a) 12% of 75

Sol :

$=\frac{12}{100}\times 75$

(b) 120% of Rs. 30

Sol :

$=\frac{120}{100}\times 30$

=36

(c) 75% of 8 m.

Sol :

$=\frac{75}{100}\times 8$

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Question 2

Express the first quantity as the percentage of the second.

(a) 8 of 32

Sol :

$=\frac{8}{32}\times 100$

=25%

(b) 63 of 105

Sol :

$=\frac{63}{105}\times 100$

=60%

(c) -8 of -64

Sol :

$=\frac{-8}{-64}\times 100=\frac{1}{8}\times 100$

=12.5%

(d) 52 of 4

Sol :

$=\frac{52}{4}\times 100$

=1300%

Question 3

Find the number whose

(a) 4% is 1.8

Sol :

$=\frac{4}{100}\times x=\frac{18}{10}$

$x=\frac{18}{10}\times \frac{100}{4}$

x=45

(b) 90% is 279

Sol :

$=\frac{100}{90}\times 279$

x=310

(c) 120% is 90

Sol :

$=\frac{100}{120}\times 90$

x=75

(d) 15% is 48

Sol :

$=\frac{100}{15}\times 48$

x=320

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Question 4

Write each decimal or fraction as a per cent.

(a) 0.7

Sol :

$=\frac{7}{10}\times 100$

=70%

(b) 0.09

Sol :

$=\frac{9}{100}\times 100$

=9%

(c) $\frac{3}{4}$

Sol :

$=\frac{3}{4}\times 100$

=75%

(d) $\frac{11}{25}$

Sol :

$=\frac{11}{25}\times 100$

=44%

(e) $\frac{8}{8}$

Sol :

$=\frac{8}{8}\times 100$

=100%

(f) $\frac{37}{100}$

Sol :

$=\frac{37}{100}\times 100$

=37%

(g) 0.94

Sol :

$=\frac{94}{100}\times 100$

=94%

(h) $\frac{19}{20}$

Sol :

$=\frac{19}{20}\times 100$

=95%

(i) 0.002

Sol :

$=\frac{2}{1000}\times 100$

=0.2%

(j) $\frac{198}{1000}$

Sol :

$=\frac{198}{1000}\times 100$

=19.8%

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Question 5

Write each percent as a decimal and as a fraction.

(a) 27%

Sol :

$=\frac{27}{100}$

=0.27

(b) 44%

Sol :

$=\frac{44}{100}$

=0.44

(c) 80%

Sol :

$=\frac{80}{100}$

=0.80

(d) 112%

Sol :

$=\frac{112}{100}$

=1.12

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Question 6

Which is greater, 0.5 or $\frac{1}{2}$ %? Explain.

Sol :

Convert $\frac{1}{2}$ % into decimal

$=\dfrac{1}{2}\times \frac{1}{100}=\frac{1}{200}$

=0.005

0.5>0.005

0.5>$\frac{1}{2}$%

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Question 7

Find each percent change.

(a) 50 to 60

Sol :

$=\frac{60-50}{50}\times 100$

$=\frac{10}{50}\times 100$

=20% increase

(b) 9 to 45

Sol :

$=\frac{95-9}{9}\times 100$

$=\frac{36}{9}\times 100$

=400% increase

(c) 400 to 300

Sol :

$=\frac{400-300}{400}\times 100$

$=\frac{100}{400}\times 100$

=25% decreased

(d) 300 to 275

Sol :

$=\frac{300-275}{300}\times 100$

$=\frac{25}{300}\times 100$

$=8\frac{1}{3}$ % decreased

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Question 8

The cost of a books was Rs. 350. The bookseller gave me 20% discount. What amount did I pay for the book?

Sol :

Cost price of book (CP)=350

Discount=20%

Selling price(SP) $=\frac{350\times 80}{100}$

=280

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Question 9

John paid Rs. 2100 for a sweater that was 30% off. What was the original price?

Sol :

S.P=2100

Discount=30%

∴ $CP=\frac{2100\times 100}{70}$

=3000

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Question 10

A can of soup had 480 mg of sodium per serving. The sodium was reduced to 360 mg per serving so that the soup could be advertised as ‘low sodium’. What was the per cent change in sodium content?

Sol :

Sodium remains=480mg

Reduce=360mg

∴Reduce quantity=(480-360)

=120mg

∴Reduce quantity in percentage

$=\frac{100\times 120}{480}$

=25%

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Question 11

A person insures goods in his house valued at Rs. 5 lakh at the rate of 5 percent. What annual premium does he pay?

Sol :

The amount of annual premium is -

Given Data :

Price of the good = ₹5 lakhs

Rate of the insurance = 5%

Amount of the annual premium will be = 5% of ₹5 lakhs

In mathematical form :

Amount of annual premium will be $=\frac{500000 \times 5}{100}$ rupees

Amount of annual premium will be = 25000 rupees

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Question 12

The customes duty on an item is $33\frac{1}{3}$ % of its value. What is the duty if the item is worth Rs. 5100?

Sol :

Item value =5100

Custom duty

$=33\frac{1}{3}$ % of 5100

$=\frac{3\times 33+1}{3}\times \frac{1}{100}\times 5100$

=1700

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Question 13

Out of 3000 candidates who appeared for an examination , 92% passed. How many passed?

Sol :

Number of candidates=3000

Passed=92%

Passed candidates

$=\frac{3000\times 92}{100}$
=2760

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Question 14

A microwave is sold for Rs. 7600 after allowing a discount of 5%. Find its marked price.

Sol :

S.P=7600

Discount=5%

Market Price(M.P)

$=\frac{7600\times 100}{95}$

=8000

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Question 15

A football team won 8 matches out of the total number of matches they played. If their win percentage was 32, then how many matches did they play in all?

Sol :

Team won=8 matches

Win percentage=32%

Number of matches they play

$=\frac{100\times 8}{32}$

=25

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Question 16

During a sale, all items are available at a discount of 30%. What could be the sale price of the following?

(a) A shirt marked at Rs. 960

Sol :

M.P of shirt=960

Discount=30%

SP of shirt

$=\frac{960\times 70}{100}$

=672

(b) A pair of shoes marked at Rs. 870

Sol :

MP of shoes=870

Discount=30%

SP of shoes

$=\frac{870\times 70}{100}$

=609

(c) A jacket marked at Rs. 4500

Sol :

MP of jacket=4500

Discount=30%

SP of jacket $=\frac{4500\times 70}{100}$

=3150

S.chand publication New Learning Composite mathematics solution of class 8 Chapter 8 Percentage and Its Application Exercise 8A

Exercise 8A

Question 1

Question 2

Question 3

Question 4

Question 5

Question 6

Question 7

Question 8

Question 9

Question 10

Question 11

Question 12

Question 13

Question 14

Question 15

Question 16

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