RS Aggarwal solution class 8 chapter 9 Percentage Exercise 9B

Exercise 9B

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Q1 | Ex-9B | Class 8 | RS AGGARWAL | chapter 9 | Percentage

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Question 1:

Tick (✓) the correct answer:
$\frac{3}{5}=?$
(a) 30%
(b) 40%
(c) 45%
(d) 60%

Answer 1:

(d) 60%

Q2 | Ex-9B | Class 8 | RS AGGARWAL | chapter 9 | Percentage

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Question 2:

Tick (✓) the correct answer:
0.8% when expressed as a decimal, is
(a) 0.08
(b) 0.008
(c) 8
(d) 0.8

Answer 2:

(b) 0.008

Q3 | Ex-9B | Class 8 | RS AGGARWAL | chapter 9 | Percentage

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Question 3:

Tick (✓) the correct answer:
6 : 5 when expressed as a percentage, is
(a) $83\frac{1}{3}\%$
(b) 90%
(c) 120%
(d) 6.5%

Answer 3:

(c) 120%

Q4 | Ex-9B | Class 8 | RS AGGARWAL | chapter 9 | Percentage

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Question 4:

Tick (✓) the correct answer:
5% of a number is 9. The number is
(a) 45
(b) 90
(c) 135
(d) 180

Answer 4:

(d) 180

Q5 | Ex-9B | Class 8 | RS AGGARWAL | chapter 9 | Percentage

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Question 5:

Tick (✓) the correct answer:
What per cent of 90 is 120?
(a) 75%
(b) $33\frac{1}{3}\%$
(c) $133\frac{1}{3}\%$
(d) none of these

Answer 5:

(c) $133\frac{1}{3}\%$

Q6 | Ex-9B | Class 8 | RS AGGARWAL | chapter 9 | Percentage

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Question 6:

Tick (✓) the correct answer:
What per cent of 10 kg is 250 g?
(a) 25%
(b) 5%
(c) 10%
(d) 2.5%

Answer 6:

(d) 2.5%

Q7 | Ex-9B | Class 8 | RS AGGARWAL | chapter 9 | Percentage

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Question 7:

Tick (✓) the correct answer:
40% of ? = 240
(a) 60
(b) 600
(c) 6000
(d) 960

Answer 7:

(b) 600

Q8 | Ex-9B | Class 8 | RS AGGARWAL | chapter 9 | Percentage

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Question 8:

Tick (✓) the correct answer:
?% of 400 = 60
(a) 6
(b) 12
(c) 15
(d) 20

Answer 8:

(c) 15

Q9 | Ex-9B | Class 8 | RS AGGARWAL | chapter 9 | Percentage

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Question 9:

Tick (✓) the correct answer:
(180% of ?) ÷ 2 = 504
(a) 400
(b) 480
(c) 600
(d) 560

Answer 9:

(d) 560

Q10 | Ex-9B | Class 8 | RS AGGARWAL | chapter 9 | Percentage

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Question 10:

Tick (✓) the correct answer:
20% of Rs 800 = ?
(a) Rs 160
(b) Rs 16
(c) Rs 1600
(d) none of these

Answer 10:

(a) Rs 160
$20\% of Rs 800$

$=Rs \left(800\times \frac{20}{100}\right)$
                     

$=Rs 160$

Q11 | Ex-9B | Class 8 | RS AGGARWAL | chapter 9 | Percentage

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Question 11:

Tick (✓) the correct answer:
In an examination, Nitin gets 98 marks. This amounts to 56% of the maximum marks. What are the maximum marks?
(a) 75
(b) 150
(c) 175
(d) 225

Answer 11:

(c) 175


            $=\frac{56x}{100}$

Q12 | Ex-9B | Class 8 | RS AGGARWAL | chapter 9 | Percentage

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Question 12:

Tick (✓) the correct answer:
A number is first increased by 10% and then reduced by 10%. The number
(a) does not change
(b) decrease by 1 %
(c) increases by 1 %
(d) none of these

Answer 12:

(b) decrease by 1 %

$\mathrm{Let} x \mathrm{be} \mathrm{the} \mathrm{number}.$

$\mathrm{A} 10\% \mathrm{increase} \mathrm{will} \mathrm{give} \mathrm{a} \mathrm{new} \mathrm{number}, \frac{110}{100}x = \frac{11}{10}x$

$\mathrm{The} \mathrm{number} \mathrm{is} \mathrm{then} \mathrm{reduced} \mathrm{by} 10\%.$

$\mathrm{The} \mathrm{new} \mathrm{number} \mathrm{will} \mathrm{be} \frac{90}{100}\left(\frac{11}{10}\mathrm{x}\right)=\frac{990}{1000}x=\frac{99}{100}x$

$\mathrm{Difference} = \mathrm{x} - \frac{99}{100}\mathrm{x}=\frac{1}{100}\mathrm{x}$

$\mathrm{Percentage} \mathrm{of} \mathrm{decrease} = \frac{1}{100}x \times \frac{1}{\mathrm{x}}\times 100 = 1\%$

Q13 | Ex-9B | Class 8 | RS AGGARWAL | chapter 9 | Percentage

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Question 13:

Tick (✓) the correct answer:
A period of 4 hours 30 min is what per cent of a day?
(a) $18\frac{3}{4}\%$
(b) 20%
(c) $16\frac{2}{3}\%$
(d) 19%

Answer 13:

(a) $18\frac{3}{4}\%$

$4 h 30 min=\left(4\times 60\times 60\right)+\left(30\times 60\right)$
               $=16200 sec$
$24 h=\left(24\times 60\times 60\right)$
      $=86400 sec$

Q14 | Ex-9B | Class 8 | RS AGGARWAL | chapter 9 | Percentage

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Question 14:

Tick (✓) the correct answer:
In an examination, 65% of the total examinees passed. If the number of failures is 420, the total number of examinees is
(a) 500
(b) 1000
(c) 1200
(d) 1625

Answer 14:

(c) 1200


                                

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Q15 | Ex-9B | Class 8 | RS AGGARWAL | chapter 9 | Percentage

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Question 15:

Tick (✓) the correct answer:
A number exceeds 20% of itself by 40. The number is
(a) 50
(b) 60
(c) 80
(d) 320

Answer 15:

(a) 50

Q16 | Ex-9B | Class 8 | RS AGGARWAL | chapter 9 | Percentage

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Question 16:

Tick (✓) the correct answer:
A number decreased by $27\frac{1}{2}\%$ gives 87. The number is
(a) 58
(b) 110
(c) 120
(d) 135

Answer 16:

(c) 120

Q17 | Ex-9B | Class 8 | RS AGGARWAL | chapter 9 | Percentage

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Question 17:

Tick (✓) the correct answer:
0.05 is what per cent of 20?
(a) 25%
(b) 2.5%
(c) 0.25%
(d) 0.025%

Answer 17:

(c) 0.25%

Q18 | Ex-9B | Class 8 | RS AGGARWAL | chapter 9 | Percentage

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Question 18:

Tick (✓) the correct answer:
One-third of 1206 is what per cent of 134?
(a) 3%
(b) 30%
(c) 20%
(d) 300%

Answer 18:

(d) 300%

Q19 | Ex-9B | Class 8 | RS AGGARWAL | chapter 9 | Percentage

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Question 19:

Tick (✓) the correct answer:
x% of y is y% of?
(a) x
(b) 100x
(c) $\frac{x}{100}$
(d) $\frac{y}{100}$

Answer 19:

(a) x

$$\begin{gathered} \mathrm{Let} \mathrm{the} \mathrm{required} \mathrm{number} \mathrm{be} z. \mathrm{Then}, \mathrm{we} \mathrm{have}: \\ x\% of y=y\% of z \\ \Rightarrow \left(y\times \frac{x}{100}\right)=\left(z\times \frac{y}{100}\right) \\ \Rightarrow \frac{yx}{100}=\frac{zy}{100} \\ \Rightarrow z=\left(\frac{yx}{100}\times \frac{100}{y}\right) \\ \Rightarrow z= x \end{gathered}$$

Q20 | Ex-9B | Class 8 | RS AGGARWAL | chapter 9 | Percentage

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Question 20:

Tick (✓) the correct answer:
What per cent of $\frac{2}{7} \mathrm{is} \frac{1}{35}?$
(a) 2.5%
(b) 10%
(c) 20%
(d) 25%

Answer 20:

(a) x