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M.C.Q (1 Marks)

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31 questions · timed · auto-graded

MCQ 11 Mark
A number when divided by $143$ leaves $31$ as remainder. What will be the remainder when the same number is divided by $13?$
  • A
    $0$
  • B
    $1$
  • C
    $3$
  • $5$
Answer
Correct option: D.
$5$
Let the number be n.
When the number is divided by $143$, leaves $31$ as remainder.
$\Rightarrow $ The given number is of the form, $143x + 31$
$\Rightarrow n = 143x + 31$, where x is the quotient
$\Rightarrow n = 13(11x) + 13(2) + 5$
$\Rightarrow n = 13(11x + 2) + 5$
So, here the remainder will be $5$ when divided by $13$
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MCQ 21 Mark
$HCF$ of $\left(2^3 \times 3^2 \times 5\right),\left(2^2 \times 3^3 \times 5^2\right)$ and $\left(2^4 \times{ }^3 \times 5^3 \times 7\right)$ is:
  • A
    $30$
     
  • B
    $48$
     
  • $60$
     
  • D
    $105$
Answer
Correct option: C.
$60$
 
$\left(2^3 \times 3^2 \times 5\right),\left(2^2 \times 3^3 \times 5^2\right)$ and $\left(2^4 \times{ }^3 \times 5^3 \times 7\right)$
$HCF = 2^2× 3 × 5 = 60$
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MCQ 31 Mark
$2.13113111311113$... is:
  • A
    An integer.
  • B
    A rational number.
  • An irrational number.
  • D
    None of these.
Answer
Correct option: C.
An irrational number.
An irrational number is a number that is non-terminating and non-repeating.
$2.13113111311113$... is neither terminating nor repeating, and hence is an irrational number.
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MCQ 41 Mark
$\pi$ is:
  • A
    An integer.
  • B
    A rational number.
  • An irrational number.
  • D
    None of these.
Answer
Correct option: C.
An irrational number.

An irrational number is a number that is non-terminating and non-repeating.
$\pi=3.1415926\dots$
Which is neither terminating nor repeating, and hence is an irrational number.

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MCQ 51 Mark
a and b are two positive integers such that the least prime factor of a is $3$ and the least prime factor of b is $5$. Then, the least prime factor of $(a + b)$ is:
  • $2$
  • B
    $3$
  • C
    $5$
  • D
    $8$
Answer
Correct option: A.
$2$
Since 3 is the least prime factor of a, and 5 is the least prime factor of b, so, $2$ cannot be a factor of either.
$\therefore$ a and b are both odd.
We know that, sum of two odd numbers is alwayas even.
So, a + b is even.
$\Rightarrow $ The least prime factor of $(a + b)$ is $2$
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MCQ 61 Mark
What is the largest number that divides 70 and 125, leaving remainders 5 and 8 respectively?
  • 13
  • B
    9
  • C
    3
  • D
    585
Answer
Correct option: A.
13

70 and 125 are divided by the largest number leaving remainders 5 and 8 respectively.
70 - 5 = 65
125 - 8 = 117
So, 65 and 117 are exactly divisible by the required number.
Thus, the required number is the HCF of 65 and 117
HCF(65, 117) = 13

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MCQ 71 Mark
Which of the following has terminating decimal expansion?
  • A
    $\frac{32}{91}$
     
  • $\frac{19}{80}$
     
  • C
    $\frac{23}{45}$
     
  • D
    $\frac{25}{42}$
Answer
Correct option: B.
$\frac{19}{80}$
 

A number is a terminating decimal, if the denominator is of the form $2^m × 5^n$, where m and n are non-negative integers.
$\frac{32}{91}=\frac{32}{7\times13}$
$\frac{19}{80}=\frac{19}{2^4\times5}$
$\frac{23}{45}=\frac{23}{3^2\times5}$
$\frac{25}{42}=\frac{25}{2\times3\times7}$
Clearly, option (b) is a terminating decimal, since its denominator is of the form $2^m × 5^n$

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MCQ 81 Mark
$\frac{1}{\sqrt{2}}$ is:
  • A
    A fraction.
  • B
    A rational number.
  • An irrational number.
  • D
    None of these.
Answer
Correct option: C.
An irrational number.

An irrational number is a number that is non-terminating and non-repeating.
$\frac{1}{\sqrt{2}}=\frac{1\times\sqrt{2}}{\sqrt{2}\times\sqrt{2}}$ ...(Rationalising the denominator)
$=\frac{\sqrt{2}}{2}$
$=\frac{1}2{}\times\sqrt{2}$
Now, $\frac{1}2{}$ is rational but $\sqrt2$ is irrational.
Product of a rational number and an irrational number is irrational.
Hence, $\frac{1}{\sqrt2}$ is an irrational number.

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MCQ 91 Mark
Which of the following rational numbers is expressible as a terminating decimal?
  • A
    $\frac{124}{165}$
     
  • B
    $\frac{131}{30}$
     
  • $\frac{2027}{625}$
     
  • D
    $\frac{1625}{462}$
Answer
Correct option: C.
$\frac{2027}{625}$
 

A number is a terminating decimal, if the denominator is of the form $2^m × 5^n$, where m and n are non-negative integers.
$\frac{124}{165}=\frac{124}{3\times5\times11}$
$\frac{131}{30}=\frac{131}{2\times3\times5}$
$\frac{2027}{625}=\frac{2027}{5^4}=\frac{2027}{2^0\times5^4}$
$\frac{1625}{462}=\frac{1625}{2\times3\times7\times11}$
Clearly, option (c) is a terminating decimal, since its denominator is of the form $2^m × 5^n$.

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MCQ 101 Mark
$2.\overline{35}$ is:
  • A
    An integer.
  • A rational number.
  • C
    An irrational number.
  • D
    None of these.
Answer
Correct option: B.
A rational number.
$2.\overline{35}=2.35353535\dots$
Which is repeating decimal number, and hence is a rational number.
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MCQ 111 Mark
The number $3.24636363...$ is:
  • A
    An integer.
  • A rational number.
  • C
    An irrational number.
  • D
    None of these.
Answer
Correct option: B.
A rational number.
$3.24636363...$
Which is repeating decimal number, and hence is a rational number.
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MCQ 121 Mark
The decimal expansion of the rational number $\frac{37}{2^2\times5}$ will terminate after:
  • A
    One decimal place.
     
  • Two decimal places.
     
  • C
    Three decimal places.
     
  • D
    Four decimal places.
Answer
Correct option: B.
Two decimal places.
 
The prime factorisation of the denominator is $2^2 × 5$
Since $2 > 1,$
The decimal expansion will terminate after 2 decimal places.
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MCQ 131 Mark
$\sqrt2$ is:
  • A
    A rational number.
  • An irrational number.
  • C
    A terminating decimal.
  • D
    A non-terminating repeating decimal.
Answer
Correct option: B.
An irrational number.

An irrational number is a number that is non-terminating and non-repeating.
$\sqrt2=1.4142135\dots$ which is neither terminating nor repeating, and hence is an irrational number.

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MCQ 141 Mark
$0.\overline{68}+0.\overline{73}=?$
  • A
    $1.\overline{41}$
  • $1.\overline{42}$
  • C
    $0.\overline{141}$
  • D
    None of these.
Answer
Correct option: B.
$1.\overline{42}$
Consider, $\text{x}=0.\overline{68}$
$\Rightarrow\text{x}=0.6868\dots\ \ \dots(\text{i})$
Multiply by $100$
$\Rightarrow\text{100x}=68.68\dots\ \ \dots(\text{ii})$
Subtracting $(i)$ from $(ii)$, we get
$\text{99x}=68$
$\Rightarrow\text{x}=\frac{68}{99}\dots(\text{A})$
Consider, $\text{x}=0.\overline{73}$
$\Rightarrow x = 0.7373... ...(iii)$
Multiply by $100$
$\Rightarrow 100x = 73.73... ...(iv)$
Subtracting $(iii)$ from $(iv)$, we get
$\text{99x}=73$
$\Rightarrow\text{x}=\frac{73}{99}\dots(\text{B})$
Adding (A) and (B), gives us
$\frac{68}{99}+\frac{73}{99}=\frac{141}{99}=1.42424\dots$
$\Rightarrow0.\overline{68}+0.\overline{73}=1.42424\dots$
$=1.\overline{42}$
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MCQ 151 Mark
The decimal representation of $\frac{71}{150}$ is:
  • A
    A terminating decimal.
     
  • A non-terminating, repeating decimal.
     
  • C
    A non-terminating and non-repeating decimal.
     
  • D
    None of these.
Answer
Correct option: B.
A non-terminating, repeating decimal.
 
A number is a terminating decimal, if the denominator is of the form $2^m× 5^n$, where m and n are non-negative integers.
The prime factorisation of the denominator is $2 × 3 × 50^2$
So, the denominator will be non- terminating.
Since $\frac{71}{150}$ is a rational number, it will surely be repeating.
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MCQ 161 Mark
What is the largest number that divides each one of $1152$ and $1664$ exactly?
  • A
    $32$
  • B
    $64$
  • $128$
  • D
    $256$
Answer
Correct option: C.
$128$
The largest number that divides each one of $1152$ and $1664$ exactly will be the $HCF$ of the numbers.
Using Euclid's Division Algorithm,
$1664 = 1152 × 1 + 512$
$1152 = 512 × 2 + 128$
$512 = 128 × 4 + 0$
So, $HCF(1152, 1664) = 128$
Hence, the largest number is $128$
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MCQ 171 Mark
$\pi$ is:
  • A
    An integer.
  • B
    A rational number.
  • An irrational number.
  • D
    None of these.
Answer
Correct option: C.
An irrational number.
An irrational number is a number that is non-terminating and non-repeating.
$\pi=3.1415926\dots$
Which is neither terminating nor repeating, and hence is an irrational number.
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MCQ 181 Mark
What is the least number that divisible by all the natural numbers from $1$ to $10$ (both inclusive)?
  • A
    $100$
     
  • B
    $1260$
     
  • $2520$
     
  • D
    $5040$
Answer
Correct option: C.
$2520$
 
To find the least number divisible by all the natural numbers is the $LCM$ of the numbers from $1$ to $10$
Find the prime factorization of each of the numbers to find the $LCM$.
$ 1,2,3,5,7,4=2^2, 6=2 \times 3,8=2^3, 9=3^2, 10=2 \times 5 $
$ \text { LCM }=2^3 \times 3^2 \times 5 \times 7=2520 $
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MCQ 191 Mark
Which of the following is a pair of co-primes?
  • A
    $(14, 35)$
  • $(18, 25)$
  • C
    $(31, 93)$
  • D
    $(32, 62)$
Answer
Correct option: B.
$(18, 25)$
Two numbers are said to be co-prime
If the $HCF$ between them is $1$
$14 = 2 \times 7$
$35 = 5 \times 7$
$HCF(14, 35) = 7$
$18 = 2 \times 3 \times 3$
$25 = 5 \times 5$
$HCF(18, 25) = 1$
$31 = 1 \times 31$
$93 = 3 \times 31$
$HCF(31, 93) = 31$
$32 = 2 \times 2 \times 2 \times 2 \times 2$
$62 = 2 \times 31$
$HCF(32, 62) = 2$
Since the $HCF(18, 25)$ is $1, 18$ and $25$ is the pair of co-primes.
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MCQ 201 Mark
Euclid's division lemma sates that for any positive integers $a$ and $b$, there exist unique integers $q$ and $r$ such that $a = bq + r,$ where r must satisfy:
  • A
    $1<\text{r}<\text{b}$
  • B
    $0<\text{r}\le\text{b}$
  • $0\le\text{r}<\text{b}$
  • D
    $0<\text{r}<\text{b}$
Answer
Correct option: C.
$0\le\text{r}<\text{b}$
Euclid's division lemma states that,
For any positive integers $a$ and $b$, there exist unique integers $q$ and $r$ such that
$\text{a}=\text{bq}+\text{r},$ where $0\le\text{r}<\text{b}$
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MCQ 211 Mark
The number $1.732$ is:
  • A
    An irrational number.
  • A rational number.
  • C
    An integer.
  • D
    A whole number.
Answer
Correct option: B.
A rational number.
Since the number is a terminating decimal number, it is a rational number.
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MCQ 221 Mark
The $HCF$ of two numbers is $27$ and their $LCM$ is $162$. If one of the numbers is $54$, what is the other number?
  • A
    $36$
  • B
    $45$
  • C
    $9$
  • $81$
Answer
Correct option: D.
$81$
Let the two $n$ umbers be $a$ and $b$.
$HCF \times LCM = ab$
$\Rightarrow 27 \times 162 = 54 \times b$
$\Rightarrow b = 81$
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MCQ 231 Mark
What is the largest number that divides $245$ and $1029,$ leaving remainder $5$ in each case?
  • A
    $15$
  • $16$
  • C
    $9$
  • D
    $5$
Answer
Correct option: B.
$16$
$245$ and $1029$ are divided by the largest number leaving remainders 5 in each case.
$245 - 5 = 240$
$1029 - 5 = 1024$
So, $240$ and $1024$ are exactly divisible by the required number.
Thus, the required number is the $HCF$ of $240$ and $1024$
$HCF(240, 1024) = 16$
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MCQ 241 Mark
On dividing a positive integer $n$ by $9$, we get $7$ as remainder. What will be the remainder if $(3n - 1)$ is divided by $9?$
  • A
    $1$
  • $2$
  • C
    $3$
  • D
    $4$
Answer
Correct option: B.
$2$
On dividing $n$ by $9$ the remainder is $7$
$\Rightarrow n = 9q + 7,$ where q is the quotient
$\Rightarrow 3n = 3(9q + 7)$
$\Rightarrow 3n = 27q + 21$
$\Rightarrow 3n - 1 = 27q + 21 - 1$
$\Rightarrow 3n - 1 = 27q + 20$
$\Rightarrow 3n - 1 = 27q + 18 + 2$
$\Rightarrow 3n - 1 = 9(3q + 2) + 2$
So, the remainder will be $2$
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MCQ 251 Mark
Which of the following is an irrational number?
  • A
    $\frac{22}{7}$
  • B
    $3.1416$
  • C
    $3.\overline{1416}$
  • $3.141141114...$
Answer
Correct option: D.
$3.141141114...$
An irrational number is a number that is non-terminating and non-repeating.
Option (a) is a rational number, while option (c) is a repeating decimal number, and so are rational numbers. Option (d) is an irrational number.
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MCQ 261 Mark
The simplest form of $\frac{1095}{1168}$ is:
  • A
    $\frac{17}{26}$
  • B
    $\frac{25}{26}$
  • C
    $\frac{13}{16}$
  • $\frac{15}{16}$
Answer
Correct option: D.
$\frac{15}{16}$

$\frac{1095}{1168}=\frac{5\times3\times73}{2\times2\times2\times2\times73}$
$=\frac{5\times3}{2\times2\times2\times2}$
$=\frac{15}{16}$

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MCQ 271 Mark
The product of two numbers is $1600$ and their $HCF$ is $5$. The $LCM$ of the numbers is:
  • A
    $8000$
  • B
    $1600$
  • $320$
  • D
    $1605$
Answer
Correct option: C.
$320$
Let the two $n$ umbers be $a$ and $b$.
$HCF \times LCM = ab$
$\Rightarrow 5 \times LCM = 1600$
$\Rightarrow LCM = 320$
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MCQ 281 Mark
$LCM$ of $ \left(2^3 \times 3 \times 5\right) \text { and }\left(2^4 \times 5 \times 7\right) $ is:
  • A
    $40$
     
  • B
    $560$
     
  • C
    $1120$
     
  • $1680$
Answer
Correct option: D.
$1680$
$ \left(2^3 \times 3 \times 5\right) \text { and }\left(2^4 \times 5 \times 7\right) $
$\text { LCM }=2^4 \times 3 \times 5 \times 7=1680 $
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MCQ 291 Mark
The decimal expansion of the number $\frac{14753}{1250}$ will terminate after:
  • A
    One decimal place.
     
  • B
    Two decimal places.
     
  • C
    Three decimal places.
     
  • Four decimal places.
Answer
Correct option: D.
Four decimal places.
The prime factorisation of the denominator is $2 × 5^2$
Since $4 > 1,$
The decimal expansion will terminate after 4 decimal places.
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MCQ 301 Mark
$\big(2+\sqrt{2}\big)$ is:
  • A
    An integer.
  • B
    A rational number.
  • An irrational number.
  • D
    None of these.
Answer
Correct option: C.
An irrational number.
An irrational number is a number that is non-terminating and non-repeating.
Now, $2$ is a rational number and $\sqrt2$ is an irrational number.
Sum of a rational number and an irrational number is irrational.
Hence, $\big(2+\sqrt{2}\big)$ is an irrational number.
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MCQ 311 Mark
If $\mathrm{a}=\left(2^2 \times 3^3 \times 5^4\right) \text { and } \mathrm{b}=\left(2^3 \times 3^2 \times 5\right)$, then $HCF (a, b) = ?$
  • A
    $90$
     
  • $180$
     
  • C
    $360$
     
  • D
    $540$
Answer
Correct option: B.
$180$
 
$ a=2^2 \times 3^3 \times 5^4 $
$ b=2^3 \times 3^2 \times 5 $
$ \operatorname{HCF}(a, b)=2^2 \times 3^2 \times 5=180$
 
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M.C.Q (1 Marks) - Maths STD 10 Questions - Vidyadip