Questions · Page 3 of 3

MCQ(1M)

MCQ 1011 Mark
The sum of $0.\overline{3}$ and $0.\overline{4}$ is:
  • A
    $\frac{7}{10}$
  • $\frac{7}{9}$
  • C
    $\frac{7}{11}$
  • D
    $\frac{7}{99}$
Answer
Correct option: B.
$\frac{7}{9}$
Let $\text{x}=0.\overline{3}$
i.e., $\text{x}=0.3333 \ ...(\text{i})​​$
$\Rightarrow10\text{x}=3.3333 \ ...(\text{ii})​​$
On subtracting $(i)$ and $(ii),$ we get
$9\text{x}=3$
$\Rightarrow\text{x}=\frac{3}{9}$
Let $\text{y}=0.\overline{4}$
i.e., $\text{y}=0.4444 \ ...(\text{i})​​$
$\Rightarrow10\text{y}=4.4444 \ ...(\text{ii})​​$
On subtracting $(i)$ and $(ii),$ we get
$9\text{y}=4$
$\Rightarrow\text{y}=\frac{4}{9}$
$\therefore0.\overline{3}+0.\overline{4}$
$=\text{x}+\text{y}=\frac{\text{3}}{\text{9}}+\frac{\text{4}}{\text{9}}=\frac{\text{7}}{\text{9}}$
Hence, the correct answer is option $(b)$.
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MCQ 1021 Mark
An irrational number between $\sqrt{2}$ and $\sqrt{3}$ is:
  • A
    $\big(\sqrt{2}+\sqrt{3}\big)$
  • B
    $\big(\sqrt{2}\times\sqrt{3}\big)$
  • C
    $5^{\frac{1}{4}}$
  • $6^{\frac{1}{4}}$
Answer
Correct option: D.
$6^{\frac{1}{4}}$
An irrational number between $a$ and $b$ is given by $\sqrt{\text{ab}}$
An irrational number between $\sqrt{2}$ and $\sqrt{3}$ is
$\sqrt{\sqrt{2}+\sqrt{3}}=\big(\sqrt{6}\big)^{\frac{1}{2}}$
$=6^{\frac{1}{2}\times\frac{1}{2}}$
$=6^{\frac{1}{4}}$
Hence, the correct answer is option $(d)$.
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MCQ 1031 Mark
Which of the following is an irrational number?
  • $\sqrt{23}$
  • B
    $\sqrt{225}$
  • C
    $0.3799$
  • D
    $7.\overline{478}$
Answer
Correct option: A.
$\sqrt{23}$
The decimal expansion of $\sqrt{23}=4.79583152 ..., $ which is non $-$ terminating, nonrecurring.
Hence, it is an irrational number.
Hence, the correct opion is $(a).$
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MCQ 1041 Mark
After simplification, $\frac{13^{\frac{1}{5}}}{13^{\frac{1}{3}}}$ is :
  • A
    $13^\frac{2}{15}$
  • B
    $13^\frac{8}{15}$
  • C
    $13^\frac{1}{3}$
  • $13^\frac{-2}{15}$
Answer
Correct option: D.
$13^\frac{-2}{15}$
$\frac{13^{\frac{1}{5}}}{13^{\frac{1}{3}}}=13^{\frac{1}{5}-\frac{1}{3}}$
$=13^{\frac{3-5}{15}}=13^{\frac{-2}{15}}$
Hence, the correct answer is option $(d)$.
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MCQ 1051 Mark
The value of $7^{\frac{1}{2}}.8^{\frac{1}{2}}$ is :
  • A
    $(28)^\frac{1}{2}$
  • $(56)^\frac{1}{2}$
  • C
    $(14)^\frac{1}{2}$
  • D
    $(42)^\frac{1}{2}$
Answer
Correct option: B.
$(56)^\frac{1}{2}$
$(7)^{\frac{1}{2}}\times(8)^{\frac{1}{2}}=(7\times8)^{\frac{1}{2}}=(56)^{\frac{1}{2}}$
Hence, the correct answer is option $(b).$
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MCQ 1061 Mark
A rational number lying between $\sqrt{2}$ and $\sqrt{3}$ is:
  • A
    $\frac{\big(\sqrt{2}+\sqrt{3}\big)}{2}$
  • B
    $\sqrt{6}$
  • $1.6$
  • D
    $1.9$
Answer
Correct option: C.
$1.6$
$\sqrt{2}=1. 414213562 ... $ and $\sqrt{3}=1. 7320508075 ... $
Hence, $1.6$ lies between $\sqrt{2}$ and $\sqrt{3}$
Hence, the correct option is $(c).$
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MCQ 1071 Mark
The simplest rationalisation factor of $\big(2\sqrt{2}-\sqrt{3}\big)$ is:
  • A
    $2\sqrt{2}+3$
  • $2\sqrt{2}+\sqrt{3}$
  • C
    $\sqrt{2}+\sqrt{3}$
  • D
    $\sqrt{2}-\sqrt{3}$
Answer
Correct option: B.
$2\sqrt{2}+\sqrt{3}$
The simplest rationalisation factor of $\big(2\sqrt{2}-\sqrt{3}\big)$ is $2\sqrt{2}+\sqrt{3}$
Hence, the correct option is $(b).$
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MCQ 1081 Mark
The value of $2.\overline{45}+0.\overline{36}$ is :
  • A
    $\frac{67}{33}$
  • B
    $\frac{24}{11}$
  • $\frac{31}{11}$
  • D
    $\frac{167}{110}$
Answer
Correct option: C.
$\frac{31}{11}$
Let $\text{x}=2.\overline{45}$
i.e., $\text{x}=2.4545 \ ...(\text{i})​​$
$\Rightarrow100\text{x}=245.4545 \ ...(\text{ii})​​$
On subtracting $(i) $ and $(ii),$ we get
$99\text{x}=243$
$\Rightarrow\text{x}=\frac{243}{99}$
Let $\text{y}=0.\overline{36}$
i.e., $\text{y}=0.3636 \ ...(\text{iii})​​$
$\Rightarrow100\text{y}=36.3636 \ ...(\text{iv})​​$
On subtracting $(iii) $ and $(iv),$ we get
$99\text{y}=36$
$\Rightarrow\text{y}=\frac{36}{99}$
$\therefore2.\overline{45}+0.\overline{36}=\text{x}+\text{y}$
$=\frac{\text{243}}{\text{99}}+\frac{\text{36}}{\text{99}}=\frac{\text{279}}{\text{99}}=\frac{\text{31}}{\text{11}}$
Hence, the correct answer is option $(c).$
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MCQ 1091 Mark
If $\sqrt{7}=2.646$ then $\frac{1}{\sqrt{7}}=?$
  • A
    $0.375$
  • $0.378$
  • C
    $0.441$
  • D
    None of these.
Answer
Correct option: B.
$0.378$
$\frac{1}{\sqrt{7}}=\frac{1}{\sqrt{7}}\times\frac{\sqrt{7}}{\sqrt{7}}$
$=\frac{\sqrt{7}}{7}$
$=\frac{1}{7}\times\sqrt{7}$
$=\frac{1}{7}\times2.646$
$=0.378$
Hence, the correct option is $(b)$.
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MCQ 1101 Mark
The simplest form of $0.12\overline{3}$ is:
  • A
    $\frac{41}{330}$
  • B
    $\frac{37}{330}$
  • C
    $\frac{41}{333}$
  • None of these.
Answer
Correct option: D.
None of these.
Let $\text{x}=0.12\overline{3}$
Then, $\text{x}=0.12333 \ ...(\text{i})$
$\therefore100\text{x}=12.333... \ (\text{ii})$
and $1000\text{x}=123.333... \ (\text{iii})$
On subtracting $(ii)$ from $(iii),$ we get
$900\text{x}=111$
$\Rightarrow\text{x}=\frac{111}{900}=\frac{37}{300}$
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MCQ 1111 Mark
The value of $\sqrt{\text{p}^{-1}\text{q}}.\sqrt{\text{q}^{-1}\text{r}}.\sqrt{\text{r}^{-1}\text{p}}$ is:
  • A
    $-1$
  • B
    $0$
  • $1$
  • D
    $2$
Answer
Correct option: C.
$1$
$\sqrt{\text{p}^{-1}\text{q}}.\sqrt{\text{q}^{-1}\text{r}}.\sqrt{\text{r}^{-1}\text{p}}$
$=\sqrt{\frac{\text{q}}{\text{p}}}.\sqrt{\frac{\text{r}}{\text{q}}}.\sqrt{\frac{\text{p}}{\text{r}}}$
$=\sqrt{\frac{\text{q}}{\text{p}}\times\frac{\text{r}}{\text{q}}\times\frac{\text{p}}{\text{r}}}$
$=\sqrt{1}$
$=1$
Hence, the correct option is $(c)$.
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MCQ 1121 Mark
The decimal expansion that a rational number cannot have is:
  • A
    $0. 25$
  • B
    $0.25\overline{28}$
  • C
    $0.\overline{2528}$
  • $0.5030030003 ... $
Answer
Correct option: D.
$0.5030030003 ... $
The decimal expansion of a rational number is either terminating or non $-$ terminating recurring.
The decimal expansion of $0.5030030003 ...$ is non $-$ terminating, non $-$ recurring, which is not a property of a rational number.
Hence, the correct opion is $(d)$.
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MCQ 1131 Mark
The product of a non $-$ zero rational number with an irrational number is always a/an:
  • irrational number.
  • B
    rational number.
  • C
    whole number.
  • D
    natural number.
Answer
Correct option: A.
irrational number.
The product if a non $-$ zero rational number with an irrational number is always an irrational number.
Hence, the correct option is $(a)$.
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MCQ 1141 Mark
The value of $(243)^{\frac{1}{5}}$ is :
  • $3$
  • B
    $-3$
  • C
    $5$
  • D
    $\frac{1}{3}$
Answer
Correct option: A.
$3$
$(243)^{\frac{1}{5}}=(3^5)^{\frac{1}{5}}$
$=3^{5\times\frac{1}{5}}=3$
Hence, the correct answer is option $(a)$.
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MCQ 1151 Mark
Simplified value of $(16)^{-\frac{1}{4}}\times\sqrt[4]{16}$ is :
  • A
    $0$
  • $1$
  • C
    $4$
  • D
    $16$
Answer
Correct option: B.
$1$
$(16)^{-\frac{1}{4}}\times\sqrt[4]{16}=(2^4)^{-\frac{1}{4}}\times(2^4)^\frac{1}{4}$
$=2^{-1}\times2^1=\frac{1}{2}\times2=1$
Hence, the correct answer is option $(b)$.
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MCQ 1161 Mark
The value of $\frac{2^\circ+7^\circ}{5^\circ}$ is :
  • A
    $0$
  • $2$
  • C
    $\frac{9}{5}$
  • D
    $\frac{1}{5}$
Answer
Correct option: B.
$2$
$\frac{2^\circ+7^\circ}{5^\circ}$
$=\frac{1+1}{1}=\frac{2}{1}=2$
Hence, the correct answer is option $(b)$.
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MCQ 1171 Mark
Choose the rational number which does not lie between $-\frac{2}{3}$ and $-\frac{1}{5}.$
  • A
    $-\frac{3}{10}$
  • $\frac{3}{10}$
  • C
    $-\frac{1}{4}$
  • D
    $-\frac{7}{20}$
Answer
Correct option: B.
$\frac{3}{10}$
Given two rational numbers are negative and $\frac{3}{10}$ is a positive rational number.
So, it does not lie between $-\frac{2}{3}$ and $-\frac{1}{5}.$
Hence, the correct opion is $(b)$.
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MCQ 1181 Mark
Which of the following is a true statment?
  • A
    The sum of two irrational numbers is an irrational number.
  • B
    The product of two irrational numbers is an irrational number.
  • C
    Every real number is always rational.
  • Every real number is either rational or irrational.
Answer
Correct option: D.
Every real number is either rational or irrational.
Consider, $\big(2+\sqrt{3}\big)$ and $\big(2-\sqrt{3}\big)$ which are two irrational numbers.
$\big(2+\sqrt{3}\big)+\big(2-\sqrt{3}\big)=4,$ which is a rational number.
Consider, $\sqrt{3}$ and $\frac{1}{\sqrt{3}}$ which are two irrational numbers.
$\sqrt{3}\times\frac{1}{\sqrt{3}}=1,$ which is a rational number.
Every real number can either be a rational number or an irrational number.
Hence, the correct opion is $(d)$.
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MCQ 1191 Mark
The value of $\sqrt[4]{\sqrt[3]{2^2}}$ is:
  • A
    $2^{-\frac{1}{6}}$
  • B
    $2^{-6}$
  • $2^{\frac{1}{6}}$
  • D
    $2^{6}$
Answer
Correct option: C.
$2^{\frac{1}{6}}$
$\sqrt[4]{\sqrt[3]{2^2}}=\sqrt[4]{\sqrt[3]{4}}=\sqrt[4]{4^{\frac{1}{3}}}$
$=4^{\frac{1}{3}\times\frac{1}{4}}=4^{\frac{1}{12}}=2^{2\times\frac{1}{12}}=2^{\frac{1}{6}}$
Hence, the correct answer is option $(c).$
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MCQ 1201 Mark
The value of $\frac{4\sqrt{12}}{12\sqrt{27}}$ is:
  • A
    $\frac{1}{9}$
  • $\frac{2}{9}$
  • C
    $\frac{4}{9}$
  • D
    $\frac{8}{9}$
Answer
Correct option: B.
$\frac{2}{9}$
$\frac{4\sqrt{12}}{12\sqrt{27}}$
$=\frac{4\sqrt{4\times3}}{12\sqrt{9\times3}}$
$=\frac{2\sqrt{3}}{3\times3\sqrt{3}}=\frac{2}{9}$
Hence, the correct answer is option $(b)$.
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MCQ 1211 Mark
Every point on a number line represents:
  • A
    a rational number.
  • B
    a natural number.
  • C
    an irrational number.
  • a unique number.
Answer
Correct option: D.
a unique number.
Every point on a number line represents a unique number.
Hence, the correct opion is $(d)$.
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MCQ 1221 Mark
A rational number equivalent to $\frac{7}{19}$ is:
  • A
    $\frac{17}{119}$
  • B
    $\frac{14}{157}$
  • C
    $\frac{21}{38}$
  • $\frac{21}{57}$
Answer
Correct option: D.
$\frac{21}{57}$
$\frac{7}{17}=\frac{7\times3}{17\times3}=\frac{21}{57}$
Hence, the correct opion is $(d).$
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MCQ 1231 Mark
Every rational number is :
  • A
    a natural number.
  • B
    a whole number.
  • C
    an integer.
  • a real number.
Answer
Correct option: D.
a real number.
A number whose square is non $-$ negative, is called a real number.
The numbers of the form $\frac{\text{p}}{\text{q}},$ where $p$ and $q$ are integers and $\text{q}\neq0,$ are known as rational numbers.
So, a rational number is a real number since $p$ and $q$ which form a rational number are integers.
Hence, the correct opion is $(d).$
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MCQ 1241 Mark
The decimal representation of an irrational number is :
  • A
    always terminating.
  • B
    either terminating or repeating.
  • C
    either terminating or non $-$ repeating.
  • neither terminating nor repeating.
Answer
Correct option: D.
neither terminating nor repeating.
A number which can neither be expressed as a terminating decimal nor as a repeating decimal is called an irrational number.
So, decimal representation of an irrational number is neither terminating nor a repeating decimal.
Hence, the correct opion is $(d)$.
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MCQ 1251 Mark
If $\sqrt{2}=1.414$ then $\sqrt{\frac{\big(\sqrt{2}-1\big)}{\big(\sqrt{2}+1\big)}}=?$
  • A
    $0.207$
  • B
    $2.414$
  • $0.414$
  • D
    $0.621$
Answer
Correct option: C.
$0.414$
$\sqrt{\frac{\big(\sqrt{2}-1\big)}{\big(\sqrt{2}+1\big)}}$
$=\sqrt{\frac{\big(\sqrt{2}-1\big)}{\big(\sqrt{2}+1\big)}\times\frac{\big(\sqrt{2}-1\big)}{\big(\sqrt{2}-1\big)}}$
$=\sqrt{\frac{\big(\sqrt{2}-1\big)^2}{\big(\sqrt{2}\big)^2-(1)^2}}$
$=\sqrt{\frac{\big(\sqrt{2}-1\big)^2}{1}}$
$=\sqrt{\big(\sqrt{2}-1\big)^2}$
$=\sqrt{2}-1$
$=1.414-1$
$=0.414$
Hence, the correct option is $(c)$.
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MCQ 1261 Mark
The simplest for of $0.\overline{32}$ is:
  • A
    $\frac{16}{45}$
  • B
    $\frac{32}{99}$
  • $\frac{29}{90}$
  • D
    None of these.
Answer
Correct option: C.
$\frac{29}{90}$
Let $\text{x}=0.\overline{32}$
Then, $\text{x}=0.3222 \ ...(\text{i})$
$\therefore10\text{x}=3.222 \ ...(\text{ii})$
and $100\text{x}=32.222 \ ...(\text{iii})$
On subtracting $(ii)$ from $(iii),$ we get
$90\text{x}=29$
$\Rightarrow\text{x}=\frac{29}{90}$
Hence, the correct option is $(c).$
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MCQ 1271 Mark
The value of $x^{p-q} \cdot x^{q-r} \cdot x^{r-p}$ is equal to:
  • A
    $0$
  • $1$
  • C
    $x$
  • D
    $x^{p q r}$
Answer
Correct option: B.
$1$
$x^{p-q} \cdot x^{q-r-r} \cdot x^{r-p}$
$=x^{p-q+q-r+r-p}$
$=x^0$
$=1$
Hence, the correct option is $(b)$.
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MCQ 1281 Mark
If $\Big(\frac{2}{3}\Big)^{\text{x}}\Big(\frac{3}{2}\Big)^\text{2x}=\frac{81}{16}$ then $x =$ ?
  • A
    $1$
  • B
    $2$
  • C
    $3$
  • $4$
Answer
Correct option: D.
$4$
$\Big(\frac{2}{3}\Big)^{\text{x}}\Big(\frac{3}{2}\Big)^\text{2x}=\frac{81}{16}$
$\Rightarrow\Big(\frac{3}{2}\Big)^{-\text{x}}\Big(\frac{3}{2}\Big)^\text{2x}=\frac{3^4}{2^4}$
$\Rightarrow\Big(\frac{3}{2}\Big)^{-\text{x}+2\text{x}}=\Big(\frac{3}{2}\Big)^4$
$\Rightarrow\Big(\frac{3}{2}\Big)^{\text{x}}=\Big(\frac{3}{2}\Big)^4$
$\Rightarrow\text{x}=4$
Hence, the correct option is $(d).$
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MCQ 1291 Mark
$\frac{\sqrt{32}+\sqrt{48}}{\sqrt{8}+\sqrt{12}}=?$
  • A
    $\sqrt{2}$
  • $2$
  • C
    $4$
  • D
    $8$
Answer
Correct option: B.
$2$
$\frac{\sqrt{32}+\sqrt{48}}{\sqrt{8}+\sqrt{12}}$
$=\frac{\sqrt{4\times8}+\sqrt{4\times12}}{\sqrt{8}+\sqrt{12}}$
$=\frac{2\sqrt{8}+2\sqrt{12}}{\sqrt{8}+\sqrt{12}}$
$=\frac{2\big(\sqrt{8}+\sqrt{12}\big)}{\sqrt{8}+\sqrt{12}}=2$
Hence, the correct answer is option $(b)$.
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MCQ 1301 Mark
An irrational number between $5$ and $6$ is:
  • A
    $\frac{1}{2}(5+6)$
  • B
    $\sqrt{5+6}$
  • $\sqrt{5\times6}$
  • D
    None of these.
Answer
Correct option: C.
$\sqrt{5\times6}$
An irrational number between $a$ and $b$ is given by $\sqrt{\text{ab}}$
So, an irrational number between $5$ and $6$ is given by $\sqrt{5\times6}$
Hence, the correct answer is option $(c).$
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MCQ 1311 Mark
If $\sqrt{2}=1.41$ then $\frac{1}{\sqrt{2}}=?$
  • A
    $0.075$
  • B
    $0.75$
  • $0.705$
  • D
    $7.05$
Answer
Correct option: C.
$0.705$
$\frac{1}{\sqrt{2}}=\frac{1}{\sqrt{2}}\times\frac{\sqrt{2}}{\sqrt{2}}$
$=\frac{\sqrt{2}}{2}$
$=\frac{1.41}{2}$
$=0.705$
Hence, the correct option is $(c).$
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MCQ 1321 Mark
The value of $0.\overline{2}$ in the form $\frac{\text{p}}{\text{q}},$ where $p$ and $q$ are integers and $\text{q}\neq0,$ is:
  • A
    $\frac{1}{5}$
  • $\frac{2}{9}$
  • C
    $\frac{2}{5}$
  • D
    $\frac{1}{8}$
Answer
Correct option: B.
$\frac{2}{9}$
$\frac{2}{9}=0.2222222...=0.\overline{2}$
Hence, the correct option is $(b)$.
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MCQ 1331 Mark
The value of $\sqrt[4]{(64)^{-2}}$ is:
  • $\frac{1}{8}$
  • B
    $\frac{1}{2}$
  • C
    $8$
  • D
    $\frac{1}{64}$
Answer
Correct option: A.
$\frac{1}{8}$
$\sqrt[4]{(64)^{-2}}=\sqrt[4]{(8^2)^{-2}}$
$=8^{-4\times\frac{1}{4}}=8^{-1}=\frac{1}{8}$
Hence, the correct answer is option $(a)$.
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MCQ 1341 Mark
The simplest for of $0.\overline{54}$ is:
  • A
    $\frac{27}{50}$
  • $\frac{6}{11}$
  • C
    $\frac{4}{7}$
  • D
    None of these.
Answer
Correct option: B.
$\frac{6}{11}$
Let $\text{x}=0.\overline{54}$
Then, $\text{x}=54.5454 \ ...(\text{i})$
$\therefore100\text{x}=54.5454 \ ...(\text{ii})$
On subtracting $(i)$ from $(ii),$ we get
$99\text{x}=54$
$\Rightarrow\text{x}=\frac{54}{99}=\frac{6}{11}$
Hence, the correct option is $(b)$.
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MCQ 1351 Mark
If $\text{x}=\frac{\sqrt{7}}{5}$ and $\frac{5}{\text{x}}=\text{p}\sqrt{7}$ then the value of $p$ is:
  • A
    $\frac{7}{25}$
  • $\frac{25}{7}$
  • C
    $\frac{7}{15}$
  • D
    $\frac{15}{7}$
Answer
Correct option: B.
$\frac{25}{7}$
$\text{x}=\frac{\sqrt{7}}{5}$ and $\frac{5}{\text{x}}=\text{p}\sqrt{7}$
$\Rightarrow\frac{5}{\sqrt{7}}=\text{p}\sqrt{7}$
$\Rightarrow\frac{25}{\sqrt{7}}=\text{p}\sqrt{7}$
$\Rightarrow\text{p}=\frac{25}{\sqrt{7}\times\sqrt{7}}=\frac{25}{7}$
Hence, the correct option is $(b)$.
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MCQ 1361 Mark
The value of $\Big(\frac{256\text{x}^{16}}{81\text{y}^4}\Big)^{-\frac{1}{4}}$ is:
  • A
    $\frac{3\text{y}}{8\text{x}^4}$
  • $\frac{3\text{y}}{4\text{x}^4}$
  • C
    $\frac{4\text{y}}{5\text{x}^4}$
  • D
    $\frac{4\text{x}^4}{3\text{y}}$
Answer
Correct option: B.
$\frac{3\text{y}}{4\text{x}^4}$
$\Big(\frac{256\text{x}^{16}}{81\text{y}^4}\Big)^{-\frac{1}{4}}=\Big(\frac{81\text{y}^{4}}{256\text{x}^{16}}\Big)^{\frac{1}{4}}$
$=\Big(\frac{3^4\text{y}^{4}}{4^4(\text{x}^4)^4}\Big)^{\frac{1}{4}}=\Big(\frac{3\text{y}}{4\text{x}^4}\Big)^{4\times\frac{1}{4}}$
$=\frac{3\text{y}}{4\text{x}^4}$
Hence, the correct option is $(b)$.
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MCQ 1371 Mark
If $(3^3)^2 = 9^x$ then $5^x= ?$
  • A
    $1$
  • B
    $5$
  • C
    $25$
     
  • $125$
Answer
Correct option: D.
$125$
$(3^3)^2 = 9^x$
$\Rightarrow (3^2)^3 = (3^2)^x$
$\Rightarrow x = 3$
Then $5^x = 5^3 = 125$
Hence, the correct option is $(d).$
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MCQ 1381 Mark
$\big(6+\sqrt{27}\big)-\big(3+\sqrt{3}\big)+\big(1-2\sqrt{3}\big)$ when simplified is:
  • A
    positive and irrational.
  • positive and rational.
  • C
    negative and irrational.
  • D
    negative and rational.
Answer
Correct option: B.
positive and rational.
$\big(6+\sqrt{27}\big)-\big(3+\sqrt{3}\big)+\big(1-2\sqrt{3}\big)$
$=6+\sqrt{27}-3-\sqrt{3}-2\sqrt{3}$
$=6-3+3\sqrt{3}-\sqrt{3}-2\sqrt{3}$
$=3$
which is positive and rational number.
Hence, the correct answer is option $(b).$
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MCQ 1391 Mark
The simplest for of $1.\overline{6}$ is:
  • A
    $\frac{833}{500}$
  • B
    $\frac{8}{5}$
  • $\frac{5}{3}$
  • D
    None of these.
Answer
Correct option: C.
$\frac{5}{3}$
Let $\text{x}=1.\overline{6}$
$\Rightarrow\text{x}=1.666 \ ...(\text{i})$
$\therefore10\text{x}=16.666 \ ...(\text{ii})$
On subtracting $(i)$ from $(ii),$ we get
$9\text{x}=15$
$\Rightarrow\text{x}=\frac{15}{9}=\frac{5}{3}$
Hence, the correct option is $(c).$
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MCQ 1401 Mark
The value of $\sqrt{5+2\sqrt{6}}$ is:
  • A
    $\sqrt{5}+\sqrt{6}$
  • B
    $\sqrt{5}-\sqrt{6}$
  • $\sqrt{3}+\sqrt{2}$
  • D
    $\sqrt{3}-\sqrt{2}$
Answer
Correct option: C.
$\sqrt{3}+\sqrt{2}$
$\sqrt{5+2\sqrt{2}}$
$=\sqrt{\big(\sqrt{2}\big)^2+\big(\sqrt{3}\big)^2+2\times\sqrt{2}\times\sqrt{3}}$
$=\sqrt{\big(\sqrt{2}+\sqrt{3}\big)^2}$
$=\sqrt{2}+\sqrt{3}$
Hence, the correct option is $(c)$.
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MCQ 1411 Mark
$(125)^{-\frac{1}{3}}=?$
  • A
    $5$
  • B
    $-5$
  • $\frac{1}{5}$
  • D
    $-\frac{1}{5}$
Answer
Correct option: C.
$\frac{1}{5}$
$(125)^{-\frac{1}{3}}=\frac{1}{(125)^{\frac{1}{3}}}$
$=\frac{1}{5^{3-\frac{1}{3}}}=\frac{1}{5}$
Hence, the correct answer is option $(c).$
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MCQ 1421 Mark
Simplified value of $(25)^{\frac{1}{3}}\times5^{\frac{1}{3}}$ is:
  • A
    $25$
  • B
    $3$
  • C
    $1$
  • $5$
Answer
Correct option: D.
$5$
$(25)^{\frac{1}{3}}\times5^{\frac{1}{3}}$
$=5^{2\times\frac{1}{3}}\times5^\frac{1}{3}$
$=5^\frac{2}{3}\times5^\frac{1}{3}$
$=5^{\frac{2}{3}+\frac{1}{3}}=5^{\frac{3}{3}}=5$
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MCQ 1431 Mark
Which of the following is a rational number?
  • A
    $1+\sqrt{3}$
  • B
    $\pi$
  • C
    $2\sqrt{3}$
  • $0$
Answer
Correct option: D.
$0$
Since, the sum and product of a rational and an irrational is always irrational.
So, $1+\sqrt{3}$ and $2\sqrt{3}$ are irrational numbers.
Also, $\pi$ is an irrational number.
And, $0$ is an integer.
So, $0$ is a rational number.
Hence, the correct option is $(d)$.
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MCQ 1441 Mark
The value of $\Big[(81)^{\frac{1}{2}}\Big]^{\frac{1}{2}}$ is :
  • $3$
  • B
    $-3$
  • C
    $9$
  • D
    $\frac{1}{3}$
Answer
Correct option: A.
$3$
$\Big[(81)^{\frac{1}{2}}\Big]^{\frac{1}{2}}$
$=\Big[\big(9^2\big)^{\frac{1}{2}}\Big]^{\frac{1}{2}}$
$=9^{2\times\frac{1}{2}\times\frac{1}{2}}$
$=9^{\frac{1}{2}}=3^{2\times\frac{1}{2}}=3$
Hence, the correct option is $(a).$
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MCQ 1451 Mark
$\sqrt{10}\times\sqrt{15}=?$
  • A
    $\sqrt{25}$
  • $5\sqrt{6}$
  • C
    $6\sqrt{5}$
  • D
    None of these.
Answer
Correct option: B.
$5\sqrt{6}$
$\sqrt{10}\times\sqrt{15}=\sqrt{5\times2}\times\sqrt{5\times3}$
$=\sqrt{5}\times\sqrt{2}\times\sqrt{5}\times\sqrt{3}=5\sqrt{6}$
Hence, the correct answer is option $(b).$
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MCQ 1461 Mark
Which of the following is a true statment?
  • A
    $\pi$ and $\frac{22}{7}$ are both rationals.
  • B
    $\pi$ and $\frac{22}{7}$ are both irrationals
  • C
    $\pi$ is rational and $\frac{22}{7}$ is irrational.
  • $\pi$ is irrational and $\frac{22}{7}$ is rational.
Answer
Correct option: D.
$\pi$ is irrational and $\frac{22}{7}$ is rational.
A number which can neither be expressed as a terminating decimal nor as a repeating decimal is called an irrational number.
So, $\pi=3.141592 ... $ is irrational.
The numbers of the form $\frac{\text{p}}{\text{q}},$ where $p$ and $q$ are integers and $\text{q}\neq0,$ are known as rational numbers.
So, $\frac{22}{7}$ is rational.
Hence, the correct option is $(d).$
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MCQ 1471 Mark
$\big(-2-\sqrt{3}\big)\big(-2+\sqrt{3}\big)$ when simplified is:
  • A
    positive and irrational.
  • positive and rational.
  • C
    negative and irrational.
  • D
    negative and rational.
Answer
Correct option: B.
positive and rational.
$\big(-2-\sqrt{3}\big)\big(-2+\sqrt{3}\big)$
$\big(-2\big)^2-\big(\sqrt{3}\big)^2$
$=4-3=1,$ which is positive and rational number.
Hence, the correct answer is option $(b)$.
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MCQ 1481 Mark
The value of $\sqrt{3-2\sqrt{2}}$ is:
  • A
    $\sqrt{3}+\sqrt{2}$
  • B
    $\sqrt{3}-\sqrt{2}$
  • C
    $\sqrt{2}+1$
  • $\sqrt{2}-1$
Answer
Correct option: D.
$\sqrt{2}-1$
$\sqrt{3-2\sqrt{2}}$
$=\sqrt{\big(\sqrt{2}\big)^2+(1)^2-2\times\sqrt{2}\times1}$
$=\sqrt{\big(\sqrt{2}-1\big)^2}$
$=\sqrt{2}-1$
Hence, the correct option is $(d).$
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MCQ 1491 Mark
If $\text{x}=3+\sqrt{8}$ then $\Big(\text{x}^2+\frac{1}{\text{x}^2}\Big)=?$
  • $34$
  • B
    $56$
  • C
    $28$
  • D
    $63$
Answer
Correct option: A.
$34$
$\text{x}=3+\sqrt{8}$
$\Rightarrow\text{x}^2=\big(3+\sqrt{8}\big)^2$
$=9+8+6\sqrt{8}=17+6\sqrt{8}$
Now, $\frac{1}{\text{x}}=\frac{1}{3+\sqrt{8}}$
$=\frac{1}{3+\sqrt{8}}\times\frac{3-\sqrt{8}}{3-\sqrt{8}}$
$=\frac{3-\sqrt{8}}{3^2-\big(\sqrt{8}\big)^2}$
$=\frac{3-\sqrt{8}}{9-8}$
$=3-\sqrt{8}$
$\Rightarrow\Big(\frac{1}{\text{x}}\Big)^2$
$=\big(3-\sqrt{8}\big)^2=9+8-6\sqrt{8}$
$=17-6\sqrt{8}$
Then, $\Big(\text{x}^2+\frac{1}{\text{x}^2}\Big)$
$=17+6\sqrt{8}+17-6\sqrt{8}=34$
Hence, the correct option is $(a).$
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MCQ 1501 Mark
$\sqrt[3]{2}\times\sqrt[4]{2}\times\sqrt[12]{32}=?$
  • $2$
  • B
    $\sqrt{2}$
  • C
    $2\sqrt{2}$
  • D
    $4\sqrt{2}$
Answer
Correct option: A.
$2$
$\sqrt[3]{2}\times\sqrt[4]{2}\times\sqrt[12]{32}$
$=\sqrt[3]{2}\times\sqrt[4]{2}\times\sqrt[12]{2^5}$
$=2^\frac{1}{3}\times2^\frac{1}{4}\times2^{5\times\frac{1}{12}}$
$=2^{\frac{1}{3}+\frac{1}{4}+\frac{5}{12}}$
$=2^{\frac{4+3+5}{12}}$
$=2^{\frac{12}{12}}$
$=2$
Hence, the correct option is $(a)$.
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MCQ(1M) - Page 3 - Maths STD 9 Questions - Vidyadip