Questions · Page 6 of 7

M.C.Q

MCQ 2511 Mark
The value of $0.\overline{23}+0.\overline{22}$ is:
  • $0.\overline{45}$
  • B
    $0.4\overline{5}$
  • C
    $0.\overline{44}$
  • D
    $0.4\overline{4}$
Answer
Correct option: A.
$0.\overline{45}$
$0.\overline{23}=0.232323$
$0.\overline{22}=0.222222$
$0.\overline{23}+0.\overline{23}=0.45454545$
$=0.\overline{45}$
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MCQ 2521 Mark
The simplest from of $0.\overline{36}$ is:
  • A
    $\frac{36}{100}$
  • $\frac{4}{11}$
  • C
    $\frac{4}{9}$
  • D
    None of these.
Answer
Correct option: B.
$\frac{4}{11}$
$0.\overline{36}=\frac{36}{36}=\frac{4\times9}{11\times9}$
$\frac{4}{11}$
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MCQ 2531 Mark
The decimal form of $\frac{1}{999}$ is:
  • A
    $0.999$
  • $0.\overline{001}$
  • C
    $0.00\overline{1}$
  • D
    $0.0\overline{01}$
Answer
Correct option: B.
$0.\overline{001}$

 When we divide $1$ by $999$ it result is $0.001001001001001$

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MCQ 2541 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 2551 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 2561 Mark
If $\text{x}=\frac{\sqrt3-\sqrt2}{\sqrt3+\sqrt2}$ and $\text{y}=\frac{\sqrt3+\sqrt2}{\sqrt3-\sqrt2},$ then $\text{x}^2+\text{xy}+\text{y}^2=$
  • A
    $101$
  • $99$
  • C
    $98$
  • D
    $102$
Answer
Correct option: B.
$99$

 $\text{x}=\frac{\sqrt3-\sqrt2}{\sqrt3+\sqrt2}$
$\therefore\text{x}=\frac{\sqrt3-\sqrt2}{\sqrt3+\sqrt2}\times\frac{\sqrt3-\sqrt2}{\sqrt3-\sqrt2}\\ \ =\frac{\big(\sqrt3-\sqrt2\big)^2}{3-2}=5-2\sqrt6$
$\text{y}=\frac{\sqrt3+\sqrt2}{\sqrt3-\sqrt2},$
$\therefore\text{y}=\frac{\sqrt3+\sqrt2}{\sqrt3-\sqrt2}\times\frac{\sqrt3+\sqrt2}{\sqrt3+\sqrt2}\\ \ =\frac{\big(\sqrt3+\sqrt{2}\big)^2}{3-2}=5+2\sqrt6$
Now, $\text{x}^2+\text{xy}+\text{y}^2$
$=\big(5 -2\sqrt6\big)^2+\big(5-2\sqrt6\big)\big(5+2\sqrt6\big)+\big(5+2\sqrt6\big)^2$
$=\big(25+24-20\sqrt6\big)+(25-24)+\big(25+24+20\sqrt6\big)$
$=49-20\sqrt6+1+49+20\sqrt6$
$=99$
Hence, correct option is $(b).$

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MCQ 2571 Mark
The value of $7^{\frac{1}{2}}\times8^{\frac{1}{2}}$ is:
  • $(56)^{\frac{1}{2}}$
  • B
    $(14)^{\frac{1}{2}}$
  • C
    $(42)^{\frac{1}{2}}$
  • D
    $(28)^{\frac{1}{2}}$
Answer
Correct option: A.
$(56)^{\frac{1}{2}}$
$7^{\frac{1}{2}}\times8^{\frac{1}{2}}$
$=(7\times8)^{\frac{1}{2}}$
$(56)^{\frac{1}{2}}$
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MCQ 2581 Mark
The value of $\left(x^{a-b}\right)^{a+b} \times\left(x^{b-c}\right)^{b+c} \times\left(x^{c-a}\right)^{c+a}$ is:
  • A
    $0$
  • $1$
  • C
    $3$
  • D
    $2$
Answer
Correct option: B.
$1$

 $\left(x^{a-b}\right)^{a+b} \times\left(x^{b-c}\right)^{b+c} \times\left(x^{c-a}\right)^{c+a}$
$\Rightarrow\text{x}^{\text{a}^{2}-\text{b}^2}\times\text{x}^{\text{b}^2-\text{c}^2}\times\text{x}^{\text{c}^2-\text{a}^2}$
$\Rightarrow\text{x}^{\text{a}^2-\text{b}^2+\text{b}^2-\text{c}^2+\text{c}^2-\text{a}^2}$
$\Rightarrow\text{x}^0=1$

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MCQ 2591 Mark
Which one of the following is not equal to $\Big(\frac{100}{9}\Big)^{-\frac{3}{2}}?$
  • A
    $\Big(\frac{9}{100}\Big)^{\frac{3}{2}}$
  • B
    $\bigg(\frac{1}{\frac{100}{9}}\bigg)^{\frac{3}{2}}$
  • C
    $\frac{3}{10}\times\frac{3}{10}\times\frac{3}{10}$
  • $\sqrt{\frac{100}{9}}\times\sqrt{\frac{100}{9}}\times\sqrt{\frac{100}{9}}$
Answer
Correct option: D.
$\sqrt{\frac{100}{9}}\times\sqrt{\frac{100}{9}}\times\sqrt{\frac{100}{9}}$

 We have to find the value of $\Big(\frac{100}{9}\Big)^{-\frac{3}{2}}$
So,
$\Big(\frac{100}{9}\Big)^{-\frac{3}{2}}=\Big(\frac{10^2}{3^2}\Big)^{-\frac{3}{2}}$
$=\frac{10^{2\times\frac{3}{2}}}{3^{2\times\frac{3}{2}}}$
$=\frac{10^{-3}}{3^{-3}}$
$\Big(\frac{100}{9}\Big)^{-\frac{3}{2}}=\frac{\frac{1}{10^3}}{\frac{1}{3^3}}$
$=\frac{1}{10\times10\times10}\times\frac{3\times3\times3}{1}$
$=\frac{3\times3\times3}{10\times10\times10}$
Since, $\Big(\frac{100}{9}\Big)^{-\frac{3}{2}}$ is equal to $\Big(\frac{100}{9}\Big)^{\frac{3}{2}},\ \frac{1}{\Big(\frac{100}{9}\Big)^{\frac{3}{2}}},\ \frac{3\times3\times3}{10\times10\times10}.$
Hence the correct choice is $d$.

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MCQ 2601 Mark
The value of $\sqrt{3-2\sqrt2},$ is:
  • $\sqrt2-1$
  • B
    $\sqrt2+1$
  • C
    $\sqrt3-\sqrt2$
  • D
    $\sqrt3+\sqrt2$
Answer
Correct option: A.
$\sqrt2-1$

 $\sqrt{3-2\sqrt2}$
$=\sqrt{2+1-2\sqrt2}$
$=\sqrt{\big(\sqrt2\big)^2+(1)^2-2\big(\sqrt2\big)(1)}$
$=\sqrt{\big(\sqrt2-1\big)^2}$
$=\sqrt2-1$
Hence, correct option is $(a).$

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MCQ 2611 Mark
Write the correct answer in the following: A rational number between $\sqrt{2}$ and $\sqrt{3}$ is
  • A
    $\frac{\sqrt{2}+\sqrt{3}}{2}$
  • B
    $\frac{\sqrt{2}\cdot\sqrt{3}}{2}$
  • $1.5$
  • D
    $1.8$
Answer
Correct option: C.
$1.5$
 We know that
$\sqrt{2}.=1.4142135...$ and $\sqrt{3}.=1.732050807...$
We see that $1.5$ is a rational number which lies between $1.4142135... $ and $1.732050807...$
Hence, $(c)$ is tthe correct answer.
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MCQ 2621 Mark
$(1296)\frac{-1}{4}=$
  • A
    $-\frac{1}{6}$
  • B
    $-6$
  • C
    $6$
  • $\frac{1}{6}$
Answer
Correct option: D.
$\frac{1}{6}$

 $(1296)\frac{-1}{4}=(6^4)^{\frac{-1}{4}}$
$=(6)^{-1}=\frac{1}{6}$

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MCQ 2631 Mark
Write the correct answer in the following: Which of the following is equal to $x$?
  • A
    $\text{x}^{\frac{12}{7}}-\text{x}^{\frac{5}{7}}$
  • B
    $\sqrt[12]{(\text{x}^4)^{\frac{1}{3}}}$
  • $(\sqrt{\text{x}^3})^{\frac{2}{3}}$
  • D
    $\text{x}^{\frac{12}{7}}\times\text{x}^{\frac{7}{12}}$
Answer
Correct option: C.
$(\sqrt{\text{x}^3})^{\frac{2}{3}}$
$a.\text{x}^{\frac{12}{7}}-\text{x}^{\frac{5}{7}}\neq\text{x}$
$b.\sqrt[12]{\text{(x}^4})^{\frac{1}{3}}=\sqrt[12]{\text{x}^{4\times\frac{1}{3}}}=\Big(\text{x}^\frac{4}{3}\Big)^\frac{1}{12}=\text{x}^{\frac{4}{3}\times\frac{1}{12}}=\text{x}^\frac{1}{9}\neq\text{x}$
$c.\Big((\text{x}^3)^\frac{1}{2}\Big)^\frac{2}{3}=\text{(x)}^{\frac{3}{2}\times\frac{2}{3}}=\text{x}^1=\text{x}$
$d.\text{x}^{\frac{12}{7}}\times\text{x}^\frac{7}{12}=\text{x}^{\frac{12}{7}+\frac{7}{12}}=\text{x}^\frac{193}{84}\neq\text{x}$
Hence, $(c)$ is the correct answer.
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MCQ 2641 Mark
A rational number equivalent to a rational number $\frac{7}{19}$ is:
  • A
    $\frac{17}{119}$
  • B
    $\frac{21}{28}$
  • $\frac{21}{57}$
  • D
    $\frac{14}{57}$
Answer
Correct option: C.
$\frac{21}{57}$

 Divide numerator and denominator by $3.$

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MCQ 2651 Mark
If $10^\text{x}=64,$ what is the value of $10^{\frac{\text{x}}{2}+1}?$
  • A
    $18$
  • B
    $42$
  • $80$
  • D
    $81$
Answer
Correct option: C.
$80$
 We have to find the value of $10^{\frac{\text{x}}{2}+1}$ provided $10^\text{x}=64$
So,
$10^{\frac{\text{x}}{2}+1}=10^{\text{x}\times\frac{1}{2}}\times10^1$
$=\sqrt[2]{10^\text{x}}\times10^1$
By substituting $10^\text{x}=64$ we get
$=\sqrt[2]{64}\times10^1$
$=\sqrt[2]{8\times8}\times10$
$=8\times10$
$=80$
Hence the correct choice is $c.$
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MCQ 2661 Mark
$\frac{1}{\sqrt9-\sqrt8}$ is equal to:
  • $3+2\sqrt2$
  • B
    $\frac{1}{3+2\sqrt2}$
  • C
    $3-2\sqrt2$
  • D
    $\frac{3}{2}-\sqrt2$
Answer
Correct option: A.
$3+2\sqrt2$

$\frac{1}{\sqrt9-\sqrt8}$
$=\frac{1}{\sqrt9-\sqrt8}\times\frac{{\sqrt9+\sqrt8}}{{\sqrt9+\sqrt8}}$
$\frac{{\sqrt9+\sqrt8}}{\big(\sqrt9\big)^2-\big(\sqrt8\big)^2}$
$=\frac{{\sqrt9+\sqrt8}}{9-8}$
$={\sqrt9+\sqrt8}$
$=3+2\sqrt2$
Hence, correct option is $(a).$

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MCQ 2671 Mark
If $10^{2 y}=25$, then $10^{-y}$ equals:
  • A
    $-\frac{1}{5}$
  • B
    $\frac{1}{50}$
  • C
    $\frac{1}{625}$
  • $\frac{1}{5}$
Answer
Correct option: D.
$\frac{1}{5}$

We have to find the value of $10^{-y}$
Given that $10^{2 y}=25$, therefore,
$10^{2 y}=25$
$\left(10^y\right)^2=5^2$
$(10^\text{y})^{2\times\frac{1}{2}}=5^{2\times\frac{1}{2}}$
$\frac{10^{\text{y}}}{1}=\frac{5}{1}$
$\frac{1}{5}=\frac{1}{10^\text{y}}$
$\frac{1}{5}=10^\text{y}$
Hence the correct option is $d.$

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MCQ 2681 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 2691 Mark
The value of $x^{p-q} x^{q-r} x^{r-p}$ is equal to:
  • A
    $x^{p q r}$
  • $1$
  • C
    $0$
  • D
    $x$
Answer
Correct option: B.
$1$

$x^{p-q} x^{q-r} x^{r-p}$
$=x^{p-q+q-r+r-p}$
$=x^0$
$=1$

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MCQ 2701 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 2711 Mark
If $\text{x}^{-2}=64,$ then $\text{x}^{\frac{1}{3}}+\text{x}^0=$
  • A
    $2$
  • B
    $3$
  • $\frac{3}{2}$
  • D
    $\frac{2}{3}$
Answer
Correct option: C.
$\frac{3}{2}$
We have to find the value of $\text{x}^{\frac{1}{3}}+\text{x}^0$ if $\text{x}^{-2}=64$
Consider,
$\text{x}^{-2}=2^6$
$\frac{1}{\text{x}^2}=2^6$
Multiply $\frac{1}{2}$ on both sides of powers we get
$\frac{1}{\text{x}^{2\times\frac{1}{2}}}=2^{6\times\frac{1}{6}}$
$\frac{1}{\text{x}}=2^3$
$\frac{1}{\text{x}}=\frac{8}{1}$
By taking reciprocal on both sides we get,
$\frac{1}{8}=​\text{x}​$
Substituting $\frac{1}{8}$ in $​​\text{x}^{\frac{1}{3}}+​​\text{x}^0$ we get
$=\Big(\frac{1}{8}\Big)^{\frac{1}{3}}+\Big(\frac{1}{8}\Big)^0$
$=\Big(\frac{1}{2^2}\Big)^{\frac{1}{3}}+\Big(\frac{1}{8}\Big)^0$
$=\frac{1}{2^{3\times\frac{1}{3}}}+1$
$=\frac{1}{2^1}+1$
$=\frac{1}{2}+1$
By taking least common multiply we get
$=\frac{1}{2}+\frac{1\times2}{1\times2}$
$=\frac{1}{2}+\frac{2}{2}$
$=\frac{1+2}{2}$
$=\frac{3}{2}$
Hence the correct choice is $c.$
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MCQ 2721 Mark
The value of $\{2-3(2-3)^3\}^3,$ is:
  • A
    $5$
  • $125$
  • C
    $\frac{1}{5}$
  • D
    $-125$
Answer
Correct option: B.
$125$

 We have to find the value of $\{2-3(2-3)^3\}^3.$ So,
$\{2-3(2-3)^3\}^3=\{2-3(-1)^3\}^3$
$=\{2(-3\times-1)^3\}^3$
$=\{2+3\}^3$
$=5^3=125$
The value of $\{2-3(2-3)^3\}^3$ is $125$
Hence the correct choice is $b.$

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MCQ 2731 Mark
If $\frac{5-\sqrt3}{2+\sqrt3}=\text{x}+\text{y}\sqrt3,$ then:
  • $x = 13, y = -7$
  • B
    $x = -13, y = 7$
  • C
    $x = -13, y = -7$
  • D
    $x = 13, y = 7$
Answer
Correct option: A.
$x = 13, y = -7$

$\frac{5-\sqrt3}{2+\sqrt3}$
$=\frac{5-\sqrt3}{2+\sqrt3}\times\frac{2-\sqrt3}{2-\sqrt3}$
$=\frac{\big(5-\sqrt3\big)\big(2-\sqrt3\big)}{(2)^2-\big(\sqrt3\big)^2}$
$=\frac{10-5\sqrt3-2\sqrt3+3}{4-3}$
$=\frac{13-7\sqrt3}{1}$
$=13-7\sqrt3$
$⇒ x = 13$ and $y = -7$
Hence, correct option is $(a).$

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MCQ 2741 Mark
$9^3+(-3)^3-6^3=?$
  • A
    $540$
  • $486$
  • C
    $270$
  • D
    $432$
Answer
Correct option: B.
$486$

 $9^3+(-3)^3-6^3$
$=729-27-216$
$=729-243$
$=486$

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MCQ 2751 Mark
An irrational number between $\frac{1}{7}$ and $\frac{2}{7}$ is:
  • A
    $\Big(\frac{1}{7}\times\frac{2}{7}\Big)$
  • B
    $\frac{1}{2}\Big(\frac{1}{7}+\frac{2}{7}\Big)$
  • $\sqrt{\frac{1}{7}\times\frac{2}{7}}$
  • D
    None of these.
Answer
Correct option: C.
$\sqrt{\frac{1}{7}\times\frac{2}{7}}$
An irrational number between $a$ and $b$ is given by $\sqrt{\text{ab}}.$
So, an irrational number between $\frac{1}{7}$ and $\frac{2}{7}$ is $\sqrt{\frac{1}{7}\times\frac{2}{7}}.$
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MCQ 2761 Mark
$23.\overline{43}$ when expressed in the form $\frac{\text{p}}{\text{q}}$ $\big(p, q $ are integers and $\text{q}\neq0\big),$ is:
  • $\frac{2320}{99}$
  • B
    $\frac{2343}{100}$
  • C
    $\frac{2343}{999}$
  • D
    $\frac{2320}{199}$
Answer
Correct option: A.
$\frac{2320}{99}$

 Let $\text{x}=23.\overline{43}=23.434343...(1)$
Now, $100\text{x}=2343.43333...(2)$
Subtracting equation $(1)$ from $(2),$ we get
$99\text{x}=2320$
$\Rightarrow\text{x}=\frac{2320}{99}$
Hence, option $(a)$ is correct.

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MCQ 2771 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 2781 Mark
If $64^{-\frac{1}{3}}\Big(64^{\frac{1}{3}}-64^\frac{2}{3}\Big)$ then $5\sqrt[\text{n}]{64}=$
  • $25$
  • B
    $\frac{1}{125}$
  • C
    $625$
  • D
    $\frac{1}{5}$
Answer
Correct option: A.
$25$

 We have to find $5\sqrt[\text{n}]{64}$ provided $\sqrt{5^\text{n}}=125$
So,
$\sqrt{5^\text{n}}=125$
$5^{\text{n}\times\frac{1}{2}}=5^3$
$\frac{\text{n}}{2}=3$
$\text{n}=3\times2$
$\text{n}=6$
Substitute $\text{n}=6$ in $5^{\sqrt[\text{n}]{64}}$ to get
$5^{\sqrt[\text{n}]{64}}=5^{2^{6\times\frac{1}{6}}}$
$=5\times5$
$=25$
Hence the value of $5^{\sqrt[\text{n}]{64}}$ is $25$
The correct choice is $a.$

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MCQ 2791 Mark
$\frac{\sqrt{3}+\sqrt{2}}{\sqrt{3}-\sqrt{2}}+\frac{\sqrt{3}-\sqrt{2}}{\sqrt{3}+\sqrt{2}}=$
  • A
    $8$
  • B
    $-10$
  • C
    $-8$
  • $10$
Answer
Correct option: D.
$10$

 $\frac{\sqrt{3}+\sqrt{2}}{\sqrt{3}-\sqrt{2}}+\frac{\sqrt{3}-\sqrt{2}}{\sqrt{3}+\sqrt{2}}$
$\Rightarrow\frac{(\sqrt{3}+\sqrt{2})^2+(\sqrt{3}-\sqrt{2})^2}{(\sqrt{3}-\sqrt{2})(\sqrt{3}+\sqrt{2})}$
$\Rightarrow\frac{(3+2+2\sqrt{6})+3+2-2\sqrt{6}}{3-2}$
$\Rightarrow10$

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MCQ 2801 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 $(c).$

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MCQ 2811 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 2821 Mark
The value of $(32)^{\frac{1}{5}}+(-7)^0+(64)^{\frac{1}{2}}$ is:
  • $11$
  • B
    $10$
  • C
    $1$
  • D
    $0$
Answer
Correct option: A.
$11$

 $(32)^{\frac{1}{5}}+(-7)^0+(64)^{\frac{1}{2}}$
$=2+1+8$
$=11$

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MCQ 2831 Mark
Which of the following is equal to $'x'?$
  • $(\sqrt{\text{x}^3})^{\frac{2}{3}}$
  • B
    $\text{x}^{\frac{12}{7}}\times\text{x}^{\frac{7}{12}}$
  • C
    $\text{x}^{\frac{12}{7}}-\text{x}^{\frac{5}{12}}$
  • D
    $\sqrt[12]{(\text{x}^4)^{\frac{1}{3}}}$
Answer
Correct option: A.
$(\sqrt{\text{x}^3})^{\frac{2}{3}}$

 $(\sqrt{\text{x}^3})^{\frac{2}{3}}$
$=(\text{x}\frac{3}{2})^{\frac{2}{3}}$
$=\text{x}$

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MCQ 2841 Mark
If $x = 2$ and $y = 4,$ then $\Big(\frac{\text{x}}{\text{y}}\Big)^{\text{x}-\text{y}}+\Big(\frac{\text{y}}{\text{x}}\Big)^{\text{y}-\text{x}}=$
  • A
    $4$
  • $8$
  • C
    $12$
  • D
    $2$
Answer
Correct option: B.
$8$

 We have to find the value of $\Big(\frac{\text{x}}{\text{y}}\Big)^{\text{x}-\text{y}}+\Big(\frac{\text{y}}{\text{x}}\Big)^{\text{y}-\text{x}}$ if $x = 2, y = 4$
Substitute $x = 2, y = 4,$ in $\Big(\frac{\text{x}}{\text{y}}\Big)^{\text{x}-\text{y}}+\Big(\frac{\text{y}}{\text{x}}\Big)^{\text{y}-\text{x}}$ to get,
$\Big(\frac{\text{x}}{\text{y}}\Big)^{\text{x}-\text{y}}+\Big(\frac{\text{y}}{\text{x}}\Big)^{\text{y}-\text{x}}$
$=\Big(\frac{2}{4}\Big)^{2-4}+\Big(\frac{4}{2}\Big)^{4-2}$
$=\Big(\frac{2}{4}\Big)^{-2}+\Big(\frac{4}{2}\Big)^{2}$
$=\Big(\frac{1}{2}\Big)^{-2}+(2)^2$
$=\Big(\frac{1}{2^{-2}}\Big)+4$
$\Big(\frac{\text{x}}{\text{y}}\Big)^{\text{x}-\text{y}}+\Big(\frac{\text{y}}{\text{x}}\Big)^{\text{y}-\text{x}}$
$=\frac{1}{\frac{1}{2^2}}+4$
$=\frac{1}{\frac{1}{4}}+4$
$=1\times\frac{4}{1}+4$
$=4+4$
$=8$
Hence the correct choice is $b.$

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MCQ 2851 Mark
Which of the following is a rational number:
  • A
    $\sqrt{180}$
  • B
    $\sqrt{31}$
  • $\sqrt{196}$
  • D
    $0.323223222322223$
Answer
Correct option: C.
$\sqrt{196}$

 Because it is the square of $14$ and can be written in the form of $\frac{\text{p}}{\text{q}}.$

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MCQ 2861 Mark
The value of $(32)^{\frac{1}{5}}+(-7)^0+(64)^{\frac{1}{2}}$ is:
  • A
    $10$
  • B
    $0$
  • $11$
  • D
    $1$
Answer
Correct option: C.
$11$

$ = 2 + 1 + 8$
$= 11$

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MCQ 2871 Mark
If $\left(3^3\right)^2=9^x$ then $5^x= ?$
  • A
    $1$
  • B
    $5$
  • C
    $25$
  • $125$
Answer
Correct option: D.
$125$

 $\left(3^3\right)^2=9^x$
$\Rightarrow\left(3^2\right)^3=\left(3^2\right)^x$
$\Rightarrow x=3$
Then $5^x=5^3=125$
Hence, the correct option is $(d).$

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MCQ 2881 Mark
The value of $\sqrt[4]{\sqrt[3]{2^2}}$ is:
  • $2^{\frac{1}{6}}$
  • B
    $2^6$
  • C
    $2^{-6}$
  • D
    $2^{\frac{-1}{6}}$
Answer
Correct option: A.
$2^{\frac{1}{6}}$
$\sqrt[4]{\sqrt[3]{2^2}}$
$=\sqrt[4]{\sqrt{2^{\frac{2}{3}}}}$
$=2^{\frac{2}{3\times4}}=2^{\frac{1}{6}}$
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MCQ 2891 Mark
$\big(6+\sqrt{27}\big)-\big(3+\sqrt{3}\big)+\big(1-2\sqrt{3}\big)$ when simplified is:
  • positive and irrational.
  • B
    positive and rational.
  • C
    negative and irrational.
  • D
    negative and rational.
Answer
Correct option: A.
positive and irrational.
positive and irrational.
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MCQ 2901 Mark
A rational number between $\sqrt{3}$ and $\sqrt{5}$ is:
  • A
    $3.1$
  • $2.1$
  • C
    $\frac{1}{2}(\sqrt{3}+\sqrt{5})$
  • D
    $\frac{1}{2}(\sqrt{3}-\sqrt{5})$
Answer
Correct option: B.
$2.1$

 $\sqrt{3}=1.73$ and $\sqrt{5}=2.236$
$2.1$ lies in between these two numbers.

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MCQ 2911 Mark
$0.\overline{001}$ when expressed in the form $\frac{\text{p}}{\text{q}}$ $\big(p, q$ are integers and $\text{q}\neq0\big),$ is:
  • A
    $\frac{1}{1000}$
  • B
    $\frac{1}{100}$
  • C
    $\frac{1}{1999}$
  • $\frac{1}{999}$
Answer
Correct option: D.
$\frac{1}{999}$

Let $\text{x}=0.\overline{001}=0.001001001...(1)$
Now, $1000\text{x}=001.001001001...(2)$
Subtracting equation $(1)$ from $(2),$ we get
$999\text{x}=1$
$\Rightarrow\text{x}=\frac{1}{999}$
Hence, option $(d)$ is correct.

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MCQ 2921 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 2931 Mark
The value of $\Big[(81)^{\frac{1}{2}}\Big]^{\frac{1}{2}}$ is:
  • $3$
  • B
    $9$
  • C
    $-3$
  • D
    $\frac{1}{3}$
Answer
Correct option: A.
$3$

 $\Big[(81)^{\frac{1}{2}}\Big]^{\frac{1}{2}}$
$=(3^4)^{\frac{1}{2}\times\frac{1}{2}}$
$=(3^4)^{\frac{1}{4}}$
$=3$

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MCQ 2941 Mark
The value of $\frac{2}{\sqrt{5}-\sqrt{3}}$ is:
  • A
    $\frac{1}{\sqrt{5}-\sqrt{3}}$
  • B
    $\sqrt{5}-\sqrt{30}$
  • $\sqrt{5}+\sqrt{30}$
  • D
    $\frac{2}{\sqrt{5}+\sqrt{3}}$
Answer
Correct option: C.
$\sqrt{5}+\sqrt{30}$
$\frac{2}{\sqrt{5}-\sqrt{3}}$
multiplying nu nominator and denominator by
$\sqrt{5}+\sqrt{3},$ we get
$\frac{2(\sqrt{5}+\sqrt{3})}{(\sqrt{5}-\sqrt{3})(\sqrt{5}+\sqrt{3})}$
$=\frac{2(\sqrt{5}+\sqrt{3})}{5-3}$
$=\sqrt{5}+\sqrt{3}$
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MCQ 2951 Mark
Decimal representation of a rational number cannot be.
  • Non$-$terminating non$-$repeating.
  • B
    Non$-$terminating repeating.
  • C
    Terminating.
  • D
    Non$-$terminating.
Answer
Correct option: A.
Non$-$terminating non$-$repeating.
Decimal representation of a rational number cannot be non$-$terminating non$-$repeating.
It is always be terminating or non terminating repeating.
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MCQ 2961 Mark
The sum of two irrational numbers is.
  • A
    Always an integer.
  • B
    Always irrational.
  • C
    Always rational.
  • Either irrational or rational.
Answer
Correct option: D.
Either irrational or rational.
The sum of two irrational numbers, in some cases, will be irrational.
However, if the irrational parts of the numbers have a zero sum $($cancel each other out$)$, the sum will be rational.
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MCQ 2971 Mark
The value of $\frac{\sqrt{48}+\sqrt{32}}{\sqrt{27}+\sqrt{18}},$ is:
  • $\frac{4}{3}$
  • B
    $4$
  • C
    $3$
  • D
    $\frac{3}{4}$
Answer
Correct option: A.
$\frac{4}{3}$

 $\sqrt{48}=\sqrt{16\times3}=4\sqrt3$
$\sqrt{32}=\sqrt{16\times2}=4\sqrt2$
$\sqrt{27}=\sqrt{9\times3}=3\sqrt3$
$\sqrt{18}=\sqrt{9\times2}=3\sqrt2$
Now, $\frac{\sqrt{48}+\sqrt{32}}{\sqrt{27}+\sqrt{18}}=\frac{4\sqrt3+4\sqrt2}{3\sqrt3+3\sqrt2}$
$=\frac{4\big(\sqrt{\not3}+\sqrt{\not2}\big)}{3\big(\sqrt{\not3}+\sqrt{\not2}\big)}$
$=\frac{4}{3}$
Hence, correct option is $(a).$

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MCQ 2981 Mark
Which of the following is a correct statement$?$
  • A
    Sum of two irrational numbers is always irrational.
  • Sum of a rational and irrational number is always an irrational number.
  • C
    Square of an irrational number is always a rational number.
  • D
    Sum of two rational numbers can never be an integer.
Answer
Correct option: B.
Sum of a rational and irrational number is always an irrational number.
$a$.Is incorrect, because sum of two irrational numbers is not an irrational number always.
 It can also be a rational number
i.e. if we add $2+\sqrt{3}$ and $2-\sqrt{3},$ sum comes out to be $2+\sqrt{\not\text{3}}+2-\sqrt{\not\text{3}}=4,$ which is a rational number.
$b$.Is correct, if a rational number is added to an irrational number means to a Non$-$ terminating$-$repeating number, the sum will also be non$-$terminating and Non$-$repeating number,
i.e an irrational number.
Example: a rational number $'2\ '$ and an irrational no $'\sqrt{3}\ '$ is added, sum $=2+\sqrt{3}$ which is again a non$-$terminating and non$-$repeating number, hence an irrational number always.
$c$.Is incorrect, Square of an irrational number is not necessarily a rational number.
Again it can be either a rational or irrational.
i.e $(\sqrt{2})^2=2 ($Rational$)$
$(2+\sqrt{3})^2=4+3+2\times2\sqrt{3}=7+4\sqrt{3}($ irrational$)$
$d$.Is incorrect, Sum of two rational numbers can be an integer and a rational number both.
i.e $\frac{1}{2}+\frac{1}{4}=\frac{3}{4}($ Rational number$)$
Hence, correct option is $(b).$
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MCQ 2991 Mark
If $a, b, c$ are positive real numbers, then $\sqrt[5]{3125\text{a}^{10}\text{b}^{5}\text{c}^{10}}$ is equal to:
  • $5\text{a}^2\text{bc}^2$
  • B
    $25\text{ab}^2\text{c}$
  • C
    $5\text{a}^3\text{bc}^3$
  • D
    $125\text{a}^2\text{bc}^2$
Answer
Correct option: A.
$5\text{a}^2\text{bc}^2$
Find value of $\sqrt[5]{3125\text{a}^{10}\text{b}^{5}\text{c}^{10}}.$
$\sqrt[5]{3125\text{a}^{10}\text{b}^{5}\text{c}^{10}}=\sqrt[5]{5^5\text{a}^{10}\text{b}^{5}\text{c}^{10}}$
$=5^{5\times\frac{1}{5}}\text{a}^{10\times\frac{1}{2}}\text{b}^{5\times\frac{1}{5}}\text{c}^{10\times\frac{1}{5}}$
$\sqrt[5]{3125\text{a}^{10}\text{b}^5\text{c}^{10}}=5\text{a}^2\text{bc}^2$
Hence the correct choice is $a.$
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MCQ 3001 Mark
If $\sqrt{13-\text{a}\sqrt{10}}=\sqrt8+\sqrt5,$ then $a =$
  • A
    $-5$
  • B
    $-6$
  • $-4$
  • D
    $-2$
Answer
Correct option: C.
$-4$

$\sqrt{13-\text{a}\sqrt10}=\sqrt8+\sqrt5$
Squaring both sides, we get
$13-\text{a}\sqrt{10}=8+5+2\sqrt{40}$
$={13}-\text{a}\sqrt{10}-{13}=2\times2\sqrt{10}$
$=-\text{a}\sqrt{10}=4\sqrt{10}$
$\Rightarrow\text{a}=-4$
Hence, correct option is $(c).$

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M.C.Q - Page 6 - Maths STD 9 Questions - Vidyadip