Questions · Page 3 of 5

M.C.Q. [1 Marks Each]

MCQ 1011 Mark
Which of the following is the square root of $7056?$
  • A
    $86$
  • B
    $34$
  • C
    $54$
  • $84$
Answer
Correct option: D.
$84$
$84$
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MCQ 1021 Mark
The square of which of the following numbers will be odd?
  • A
    $42$
  • B
    $54$
  • C
    $66$
  • $81$
Answer
Correct option: D.
$81$

$\therefore 81$ is odd
$\therefore$ Its square will be odd.

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MCQ 1031 Mark
The unit digit number $132$ is in the square of the:
  • A
    $1$
  • B
    $2$
  • C
    $3$
  • $4$
Answer
Correct option: D.
$4$
$2 \times 2 = 4$
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MCQ 1051 Mark
Which of the following is the difference between the squares of two consecutive natural number is:
  • Sum of the two numbers.
  • B
    Difference of the numbers.
  • C
    Twice the sum of the two numbers.
  • D
    Twice the difference between the two numbers.
Answer
Correct option: A.
Sum of the two numbers.
A.  Sum of the two numbers.
Solution:
Let the number be (a) and $(a-1)$
Difference between the square.
$= a^2 – (a + b)^2$
= inserting the formula... ${a^2 – b^2 = (a + b)(a - b)}$
$= (a - a + 1)(a + a- 1)$
$= (1)(2a - 1)$
$= 2a - 1$
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MCQ 1061 Mark
Mark $(\checkmark)$ against the correct answer Which of the following numbers is not a perfect square?
  • A
    $529$
  • B
    $961$
  • C
    $1024$
  • $1222$
Answer
Correct option: D.
$1222$
A number ending in $2, 3, 7$ or $8$ is not a perfect square.
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MCQ 1071 Mark
The smallest number by which $1000$ should be divided so as to get a perfect square is:
  • A
    $5$
  • $10$
  • C
    $100$
  • D
    $1000$
Answer
Correct option: B.
$10$
B.  $10$
Solution:
$1000 \div 10 = 100 = 10^2$
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MCQ 1081 Mark
What is the sum of the first four odd natural numbers?
  • A
    $18$
  • $16$
  • C
    $17$
  • D
    $20$
Answer
Correct option: B.
$16$

The sum of the first odd natural numbers $= 1 + 3 + 5 + 7 = 16$

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MCQ 1091 Mark
Express the square number $5^2$ as the sum of two consecutive integers.
  • $12 + 13$
  • B
    $10 + 15$
  • C
    $9 + 16$
  • D
    $20 + 5$
Answer
Correct option: A.
$12 + 13$
A.  $12 + 13$
Solution:
$\frac{5^2-1}{2} = 12, \frac{5^2+1}{2} = 13$
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MCQ 1101 Mark
The sum of first $n$ odd natural numbers is:
  • A
    $2n + 1$
  • $n^2$
  • C
    $n^2 - 1$
  • D
    $n^2 + 1$
Answer
Correct option: B.
$n^2$
B.  $n^2$
Solution:
Sum of frist n odd natural numbers $=\sum(2\text{n}-1)=2\sum\text{n}-\text{n}$
$=\frac{2\times\text{n}(\text{n}+1)}{2}-\text{n}=\text{n}(\text{n}+1)-\text{n}$
$=\text{n}^2+\text{n}-\text{n}=\text{n}^2$
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MCQ 1121 Mark
If a number of n-digits is perfect square and $‘n’$ is an odd number, then which of the following is the number of digits of its square root?
  • A
    $\frac{\text{n-1}}{2}$
  • B
    $\frac{\text{n}}{2}$
  • $\frac{\text{n+1}}{2}$
  • D
    $\text{2n}$
Answer
Correct option: C.
$\frac{\text{n+1}}{2}$

No of digits in a perfect square is n
If n is odd then no of digits in its square roots is $\frac{\text{n+1}}{2}$

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MCQ 1131 Mark
A perfect square number having $n$ digits where $n$ is even will have square root with:
  • A
    $\text{n}+1\text{ digit}$
  • $\frac{\text{n}}{2}\text{ digit}$
  • C
    $\frac{\text{n}}{3}\text{ digit}$
  • D
    $\frac{\text{n}+1}{2}\text{ digit}$
Answer
Correct option: B.
$\frac{\text{n}}{2}\text{ digit}$
A perfect square number having $n$ digits, where $n$ is even, will have square root with $\frac{\text{n}}{2}\text{ digit}.$
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MCQ 1141 Mark
Which of the following cannot be a perfect square?
  • A
    $841$
  • B
    $529$
  • $198$
  • D
    All of the above.
Answer
Correct option: C.
$198$

We know that, a number ending with digits $2, 3, 7$ or $8$ can never be a perfect square. So, $198$ cannot be written in the form of a perfect square.

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MCQ 1151 Mark
Which of the following will have $4$ at the units place?
  • A
    $14^2$
  • $62^2$
  • C
    $27^2$
  • D
    $35^2$
Answer
Correct option: B.
$62^2$
B.  $62^2$
Solution:
The unit place of the square of $14=4^2=16=6$
The unit place of the square of $62-2^2=4\left[\because 2^2=4\right]$
The unit place of square of $27=7^2=49=9$
The unit place of the square of $35=5^2=52=5$
Clearly, $62^2$ has 4 at the unit's place.
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MCQ 1161 Mark
The least number which must be subtracted from $6156$ to make its perfect square is:
  • A
    $52$
  • B
    $82$
  • $72$
  • D
    $62$
Answer
Correct option: C.
$72$
$72$
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MCQ 1171 Mark
Which of the following is a Pythagorean-triplet?
  • A
    $n, (n^2 - 1)$ and $(n^2+ 1)$
  • B
    $(n - 1), (n^2 - 1)$ and $(n^2 + 1)$
  • C
    $(n + 1), (n^2 - 1)$ and $(n^2 + 1)$
  • $2n, (n^2 - 1)$ and $(n^2 + 1)$
Answer
Correct option: D.
$2n, (n^2 - 1)$ and $(n^2 + 1)$
D.  $2n, (n^2 - 1)$ and $(n^2 + 1)$
Solution:
$2n, (n^2 - 1)$ and $(n^2 + 1)$ is a Pythagorean - triplet.
Example: Let $2n = 6$
$\therefore$ $n = 3$
Now, $n^2 - 1 = 32 - 1 = 8$
And $n^2 + 1 = 32 + 1 = 10$
Thus the required Pythagorean triplet is $6,8,10.$
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MCQ 1181 Mark
The smallest number by which $48$ should be divided so as to get a perfect square is:
  • A
    $2$
  • $3$
  • C
    $4$
  • D
    $6$
Answer
Correct option: B.
$3$
B.  $3$
Solution:
$48 \div 3 = 16 = 4^2$
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MCQ 1191 Mark
A perfect square that lies between $40$ and $50$ is:
  • A
    $42$
  • B
    $45$
  • $49$
  • D
    $46$
Answer
Correct option: C.
$49$
C.  $49$
Solution:
$49$ is a perfect square.
$49 = 7 \times 7 = 7^2$
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MCQ 1201 Mark
Which of the following numbers would have digit $6$ at unit place?
  • A
    $19^2$
  • B
    $25^2$
  • C
    $28^2$
  • $26^2$
Answer
Correct option: D.
$26^2$
D.   $26^2$
Solution:
$19^2 = 361. $So, the unit digit is $1.$
$25^2 = 625. $So, the unit digit is$ 5.$
$28^2 = 784.$ So, the unit digit is $4.$
$26^2 = 676.$ So, the unit digit is$ 6.$
The unit place of $262$ have $6$ at the unit place.
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MCQ 1211 Mark
Which of the following is the number of zeros in the square of $900\ ?$
  • A
    $3$
  • B
    $4$
  • $5$
  • D
    $2$
Answer
Correct option: C.
$5$
B.  $4$
Solution:
To find:
The number of zeros in the square of $900$
We know that,
The number of zeros of a numnber gets double when the number is squared.
Consider,
Number of zeros in $900$ is $2$
Then, the number of zeros in square of $900$ is $4$
Verification, $900^2 = 810000$
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MCQ 1221 Mark
What is the length of the side of a square whose area is $441\ cm^2\ ?$
  • $21$
  • B
    $22$
  • C
    $20$
  • D
    $12$
Answer
Correct option: A.
$21$
A.  $21$
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MCQ 1231 Mark
Which of the following numbers is a perfect cube?
  • A
    $243$
  • $216$
  • C
    $392$
  • D
    $8640$
Answer
Correct option: B.
$216$
$a. (b)$ For option $(a)$ We have, $243$
Resolving $243$ into prime factors, we have
$243 = 3 \times 3 \times 3 \times 3 \times 3$
Grouping the factors in triplets of equal factors, we get,
$243 = (3 \times 3 \times 3) \times 3 \times 3$
Clearly, in grouping, the factors in triplets of equal factors, we are left with two factors $3 \times 3.$
Therefore, $243$ is not a perfect cube.
$b.$ For option $(b)$ We have, $216$ Resolving $216$ into prime factors, we have
$216 = 2 \times 2 \times 2 \times 3 \times 3 \times 3$
Grouping the factors in triplets of equal factors, we get $216 = (2 \times 2 \times 2) \times (3 \times 3 \times 3)$
Clearly, in grouping, the factors of triplets of equal factors, no factor is left over.
So, $216$ is a perfect cube.
$c.$ or option $(c)$ We have, $392$
Resolving $392$ into prime factors, we get
$392 = 2 \times 2 \times 2 \times 7 \times 7$
Grouping the factors in triplets of equal factors, we get
$392 = (2 \times 2 \times 2) \times 7 \times 7$
Clearly, in grouping, the factors in triplets of equal factors, we are left with two factors $7 \times 7.$
Therefore, $392$ is not a perfect cube.
$d.$ For option $(d)$ We have, $8640$
Resolving $8640$ into prime factors, we get,
$8640 = 2 \times 2 \times 2 \times 2 \times 2 \times 2 \times 3 \times 3 \times 3 \times 5$
Grouping the factors in triplets of equal factors, we get, $8640 = (2 \times 2 \times 2) \times (2 \times 2 \times 2) \times (3 \times 3 \times 3) \times 5$
Clearly, in grouping, the factors in triplets of equal factors, we are left with one factor $5.$
Therefore, $8640$ in not a perfect cube.
After solving, it is clear that option $(b)$ is correct.
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MCQ 1241 Mark
Express $7^2$ as the sum of two consecutive integers.
  • A
    $40 + 9$
  • $24 + 25$
  • C
    $36 + 13$
  • D
    $32 + 17$
Answer
Correct option: B.
$24 + 25$
B.  $24 + 25$
Solution:
$\frac{7^2-1}{2}=24, \frac{5^2+1}{2}=25$
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MCQ 1251 Mark
Tick $(\checkmark)$ the correct answer of the following: $\frac{\sqrt{288}}{\sqrt{128}}=\ ?$
  • A
    $\frac{\sqrt3}{2}$
  • B
    $\frac{3}{\sqrt2}$
  • $\frac{3}{2}$
  • D
    $1.49$
Answer
Correct option: C.
$\frac{3}{2}$
$\frac{\sqrt{288}}{\sqrt{128}}$
$=\sqrt{\frac{288}{128}}$
$=\sqrt{\frac{9}{4}}$
$=\frac{3}{2}$
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MCQ 1261 Mark
What is the length of side of a square, if the area of square is $441\ cm^2\ ?$
  • A
    $29\ cm$
  • $21\ cm$
  • C
    $39\ cm$
  • D
    $31\ cm$
Answer
Correct option: B.
$21\ cm$
B.  $21\ cm$
Solution:
Area of a square $= 441\ cm^2$
By the formula, we know that;
Area of a square $=$ side$^2$
$441 = $ side$^2$
Side $=\sqrt{441}=21$
Therefore, length of side of square is $21\ cm.$
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MCQ 1271 Mark
If m is the square of a natural number n, then n is:
  • A
    The square of m.
  • B
    Greater than m.
  • C
    Equal to m.
  • $\sqrt{\text{m}}.$
Answer
Correct option: D.
$\sqrt{\text{m}}.$
D.  $\sqrt{\text{m}}.$
Given, m is the square of n, i,. $m = n^2$
Taking square root both sides, we get
$\text{n}=\sqrt{\text{m}}$
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MCQ 1281 Mark
Mark $(\checkmark)$ against the correct answerWhat least number must be subtracted from $178$ to make it a perfect square?
  • A
    $6$
  • B
    $8$
  • $9$
  • D
    $7$
Answer
Correct option: C.
$9$
$178-9=169$
$\sqrt{169}=13$
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MCQ 1291 Mark
$\sqrt{\frac{1}{16}+\frac{1}{9}}=$
  • $\frac{5}{12}$
  • B
    $\frac{7}{12}$
  • C
    $\frac{25}{44}$
  • D
    None of these.
Answer
Correct option: A.
$\frac{5}{12}$
$\frac{5}{12}$
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MCQ 1301 Mark
The sum of $1 + 3 + 5 + 7 + 9 + 11 + 13 + 15 + 17 + 19$ is:
  • A
    $120$
  • $100$
  • C
    $121$
  • D
    $110$
Answer
Correct option: B.
$100$
Sum of n odd numbers $= 1 + 3 + 5 + 7 + 9 + 11 + 13 + 15 + 17 + 19 = 100$
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MCQ 1311 Mark
Which of the following is a perfect square?
  • A
    $7928$
  • B
    $64000$
  • $625$
  • D
    $1057$
Answer
Correct option: C.
$625$
The natural numbers which end with $0, 2, 3, 7$ and $8$ are not perfect squares.
Hence, $625$ is a perfect square.
$25 × 25 = 625$
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MCQ 1321 Mark
Tick $(\checkmark)$ the correct answer of the following: $\sqrt{0.9}=\ ?$
  • A
    $0.3$
  • B
    $0.03$
  • C
    $0.33$
  • $0.94$
Answer
Correct option: D.
$0.94$

$\begin{array}{c|c}&0.94\\\hline9&0.\overline{90}\ \overline{00}\\&\ \ \ \ 81\ \ \ \ \ \\\hline184&\ \ \ \ \ \ 900\\&\ \ \ \ \ \ \ 736\\\hline&\ \ \ \ \ \ \ \ 164\\\end{array}$

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MCQ 1331 Mark
Tick $(\checkmark)$ the correct answer of the following: What least number must be added to $15370$ to make it a perfect square?
  • A
    $4$
  • $6$
  • C
    $8$
  • D
    $9$
Answer
Correct option: B.
$6$
(B) $6$
Solution:
Finding the square root of $15370$ by division method
We get Remainder $= 261$
Now $(123)^2 = 15129$
and $(124)^2 = 15379$
The least number to be added
$= 15129 - 15379 = 6$
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MCQ 1341 Mark
The smallest number by which $32$ should be multiplied so as to get a perfect square is:
  • $2$
  • B
    $3$
  • C
    $4$
  • D
    $8$
Answer
Correct option: A.
$2$
$32 \times 2 = 64 = 8^2$
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MCQ 1351 Mark
The number of digits in the square root of $62500$ is:
  • A
    $1$
  • B
    $2$
  • $3$
  • D
    $4$
Answer
Correct option: C.
$3$
$\text{n}=5,\frac{\text{n}+1}{2} = 3$
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MCQ 1361 Mark
Express $9^2$ as the sum of two consecutive integers.
  • $40 + 41$
  • B
    $50 + 31$
  • C
    $36 + 45$
  • D
    $72 + 9$
Answer
Correct option: A.
$40 + 41$
$\frac{9^2-1}{2}=40, \frac{5^2+1}{2}=41$
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MCQ 1371 Mark
What could be the possible one’s digit of the square root of $625$?
  • A
    $2$
  • B
    $3$
  • C
    $4$
  • $5$
Answer
Correct option: D.
$5$
$5 \times 5 = 25$
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MCQ 1381 Mark
If a number of n-digits is a perfect square and $‘n’$ is an even number, then which of the following is the number of digits of its square root?
  • A
    $\frac{\text{n-1}}{2}$
  • $\frac{\text{n}}{2}$
  • C
    $\frac{\text{n+1}}{2}$
  • D
    $\text{2n}$
Answer
Correct option: B.
$\frac{\text{n}}{2}$

Number of digit of the perfect square $(n)$
Number of digits of the square root $\frac{\text{n}}{2}$ (when $'n'$ is even)
Example:
$1296$ (is perfect square) and $n = 4$ (even number)
$\therefore $ Number of digits of its square root $=\frac{\text{n}}{2}$
$=\frac{4}{2}=2$
Now $ \sqrt{1296} =36$ ($2$ - digits).

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MCQ 1391 Mark
Find the perfect square numbers between $30$ and $40$.
  • $36$
  • B
    $49$
  • C
    $25$
  • D
    None of these.
Answer
Correct option: A.
$36$
$36$
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MCQ 1401 Mark
Which of the following is a perfect square number?
  • A
    $1067$
  • B
    $7828$
  • C
    $4333$
  • $625$
Answer
Correct option: D.
$625$
Perfect square numbers end with
$0, 1, 4, 5, 6$ or $9$ at unit’s place.
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MCQ 1411 Mark
Which of the following arc the factors of $1 – x^2\ ?$
  • A
    $(x + l)(x – I)$
  • $(1 – x)(1 + x)$
  • C
    $(1 – x)(1 – x)$
  • D
    $(1 + x)(1 + x)$
Answer
Correct option: B.
$(1 – x)(1 + x)$
 $(1 – x)(1 + x)$
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MCQ 1421 Mark
The number of digits in the square root of $441$ is:
  • A
    $1$
  • $2$
  • C
    $3$
  • D
    $4$
Answer
Correct option: B.
$2$

$\text{n}=3, \frac{\text{n+1}}{2}=2$

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MCQ 1431 Mark
There are $588$ students in a school. For a mock drill they have to stand in such a manner that the number of rows is equal to number of columns. How many children would be left out in this arrangement?
  • A
    $13$
  • B
    $15$
  • $12$
  • D
    $18$
Answer
Correct option: C.
$12$
Here, Number of children $= 588$
By getting the square root of this number, we get,
In each row, the number of students is $24$.
And left out children are $12$.
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MCQ 1441 Mark
Find the length of the side of a square whose area is $100\ cm^2.$
  • A
    $5\ cm$
  • $10\ cm$
  • C
    $100\ cm$
  • D
    $4\ cm$
Answer
Correct option: B.
$10\ cm$
$\sqrt{100}=10\text{cm}$
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MCQ 1451 Mark
Which of the following Pythagorean triplet has the smallest member $‘8’$.
  • $8, 15, 17$
  • B
    $8, 10, 12$
  • C
    $8, 9, 10$
  • D
    $8, 11, 14$
Answer
Correct option: A.
$8, 15, 17$
$8, 15, 17$
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MCQ 1461 Mark
Tick $(\checkmark)$ the correct answer of the following: Which of the following numbers is not a perfect square?
  • $1843$
  • B
    $3721$
  • C
    $1024$
  • D
    $1296$
Answer
Correct option: A.
$1843$
$1843$ as it has $3$ in the end.
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MCQ 1471 Mark
Which of the following is the number of non-perfect square number between $17^2$ and $18^2\ ?$
  • A
    $613$
  • B
    $35$
  • $34$
  • D
    $70$
Answer
Correct option: C.
$34$
Question should be read as:
Non perfect square nunbers between $17^2$ and $18^2$
$17 = n$
$18 = n + 1$
(question for finding, non perfect square nunbers between $17^2$ and $18^2 = 2n$)
$\therefore $ non perfect square nunbers between $17^2$ and $18^2 = 2n$
$= 2 \times 17$
$= 34$
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MCQ 1481 Mark
The Pythagorean triples whose smallest number is $8:$
  • A
    $8, 17, 18$
  • B
    $8, 16 17$
  • C
    $8, 15, 16$
  • $8, 15, 17$
Answer
Correct option: D.
$8, 15, 17$
The general form of Pythagorean triplets is $2m, m^2- 1, m^2+ 1$
Given, $2m = 8$
So $, m = 4$
$m^2 - 1 = 4^2- 1 = 16 - 1 = 15$
$m^2+ 1 = 4^2+ 1 = 16 + 1 = 17$
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MCQ 1491 Mark
The value of $(501)^2 - (500)^2$ is:
  • A
    $101$
  • B
    $1$
  • $1001$
  • D
    None of these.
Answer
Correct option: C.
$1001$
 $1001$
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MCQ 1501 Mark
Which of the following can be a perfect square?
  • A
    A number ending in $3$ or $7$
  • B
    A number ending with odd number of zeros
  • A number ending with even number of zeros
  • D
    A number ending in $2$
Answer
Correct option: C.
A number ending with even number of zeros
The number of zeros at the end of a perfect square are always even in number.
Let's the see the ending numbers of perfect squares:
$1, 4, 9, 16, 25, 36, 49, 64, 81, ....$
So, the ending digits are $1, 4, 5, 6, 9$
In the case $(i)$ and $(iv)$
From the above digits we can see that there are no perfect squares with $3,7$ or $2$ as ending digits.
In the case $(ii)$
A perfect square always has even number of ending zeroes:
eg. $10^2 = 100$
$100^2 = 10,000$
$1000^2 = 10,00,000$
So, the answer is $(iii)$.
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M.C.Q. [1 Marks Each] - Page 3 - MATHS STD 8 Questions - Vidyadip