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Quantitative Aptitude

SQUARE ROOT AND CUBE ROOT MCQs

Square Roots, Cube Roots, Squares And Square Roots

Total Questions : 547 | Page 38 of 55 pages
Question 371.
The largest four digit number which is a perfect cube, is



  1.    8000
  2.    9261
  3.    9999
  4.    None of these
 Discuss Question
Answer: Option B. -> 9261

Clearly, 9261 is a perfect cube satisfying the given property.



Question 372.

0.0169 x ? = 1.3


  1.    10
  2.    100
  3.    1000
  4.    None of these
 Discuss Question
Answer: Option B. -> 100

Let 0.0169 x x = 1.3.

Then, 0.0169x = (1.3)2 = 1.69

 0.0169 X ? = 1.3  x = 1.69 = 100 0.0169


Question 373.
$MF#%\dfrac{{\sqrt{144}}}{11} \times \dfrac{11}{{\sqrt{225}}} \times \dfrac{15}{{\sqrt{196}}} \text{ is equal to:}$MF#%
  1.    0.85
  2.    0.72
  3.    2.8
  4.    0.4
 Discuss Question
Answer: Option A. -> 0.85

Answer : Option A

Explanation :

$MF#%\dfrac{{\sqrt{144}}}{11} \times \dfrac{11}{{\sqrt{225}}} \times \dfrac{15}{{\sqrt{196}}}\\\\
=\dfrac{{12}}{11} \times \dfrac{11}{{15}} \times \dfrac{15}{{14}}\\\\
=\dfrac{12}{14} \\\\= \dfrac{6}{7}\\\\ = 0.85\\\\$MF#%


Question 374.

A group of students decided to collect as many paise from each member of group as is the number of members. If the total collection amounts to Rs. 59.29, the number of the member is the group is:


  1.    57
  2.    67
  3.    77
  4.    87
 Discuss Question
Answer: Option C. -> 77

Money collected = (59.29 x 100) paise = 5929 paise.

 A Group Of Students Decided To Collect As Many Paise From E... Number of members = 5929 = 77.


Question 375.
How many two-digit numbers satisfy this property : The last digit (units digit) of the square of the two-digit number is 8 ?
  1.    1
  2.    2
  3.    3
  4.    None of these
 Discuss Question
Answer: Option D. -> None of these

Answer : Option D

Explanation :

A number ending with 8 can never become a perfect square
Let's examine this in detail
1 × 1 = 1
Hence, if the unit digit of a number is 1, unit digit of its square is 1
2 × 2 = 4
Hence, if the unit digit of a number is 2, unit digit of its square is 4
3 × 3 = 9
Hence, if the unit digit of a number is 3, unit digit of its square is 9
4 × 4 = 16
Hence, if the unit digit of a number is 4, unit digit of its square is 6
5 × 5 = 25
Hence, if the unit digit of a number is 5, unit digit of its square is 5
6 × 6 = 36
Hence, if the unit digit of a number is 6, unit digit of its square is 6
7 × 7 = 49
Hence, if the unit digit of a number is 7, unit digit of its square is 9
8 × 8 = 64
Hence, if the unit digit of a number is 8, unit digit of its square is 4
9 × 9 = 81
Hence, if the unit digit of a number is 9, unit digit of its square is 1
0 × 0 = 0
Hence, if the unit digit of a number is 0, unit digit of its square is 0


Question 376.
The square root of 16641 is
  1.    129
  2.    121
  3.    211
  4.    229
 Discuss Question
Answer: Option A. -> 129

Answer : Option A

Explanation :

$MF#%\sqrt{16641} = 129$MF#%


Question 377.
$MF#%\dfrac{\dfrac{1}{\sqrt{9}}-\dfrac{1}{\sqrt{11}}}{\dfrac{1}{\sqrt{9}}+\dfrac{1}{\sqrt{11}}}+\dfrac{10 + \sqrt{99}}{?}=\dfrac{1}{2}$MF#%
  1.    1
  2.    2
  3.    3
  4.    4
 Discuss Question
Answer: Option B. -> 2

Answer : Option B

Explanation :

$MF#%\begin{align}&\left[\dfrac{\dfrac{1}{\sqrt{9}}-\dfrac{1}{\sqrt{11}}}{\dfrac{1}{\sqrt{9}}+\dfrac{1}{\sqrt{11}}}\right]+\left[\dfrac{10 + \sqrt{99}}{x}\right]=\dfrac{1}{2}\\\\
&\Rightarrow \left[\dfrac{\sqrt{11}-\sqrt{9}}{\sqrt{11}+\sqrt{9}}\right]+\left[\dfrac{10 + \sqrt{99}}{x}\right]=\dfrac{1}{2}\\\\
&\Rightarrow \left[\dfrac{\left(\sqrt{11}-\sqrt{9}\right)\left(\sqrt{11}-\sqrt{9}\right)}{\left(\sqrt{11}+\sqrt{9}\right)\left(\sqrt{11}-\sqrt{9}\right)}\right]+\left[\dfrac{10 + \sqrt{99}}{x}\right]=\dfrac{1}{2}\\\\
&\Rightarrow \left[\dfrac{\left(\sqrt{11}-\sqrt{9}\right)^2}{11-9}\right]+\left[\dfrac{10 + \sqrt{99}}{x}\right]=\dfrac{1}{2}\\\\
&\Rightarrow \left[\dfrac{11-2\sqrt{11}\sqrt{9}+9}{2}\right]+\left[\dfrac{10 + \sqrt{99}}{x}\right]=\dfrac{1}{2}\\\\
&\Rightarrow \left[\dfrac{20-2\sqrt{99}}{2}\right]+\left[\dfrac{10 + \sqrt{99}}{x}\right]=\dfrac{1}{2}\\\\
&\Rightarrow \left(10-\sqrt{99}\right)+\left[\dfrac{10 + \sqrt{99}}{x}\right]=\dfrac{1}{2}\\\\
&\Rightarrow \dfrac{\left(10-\sqrt{99}\right) \left(10+\sqrt{99}\right)}{x}=\dfrac{1}{2}\\\\
&\Rightarrow \dfrac{\left(100-99\right)}{x}=\dfrac{1}{2}\\\\
&\Rightarrow \dfrac{1}{x}=\dfrac{1}{2}\\\\
&\Rightarrow x=2\end{align}$MF#%


Question 378.
If x = 1 + √2 and y = 1 - √2, find the value of (x2 + y2).



  1.    8
  2.    7
  3.    6
  4.    5
 Discuss Question
Answer: Option C. -> 6

x2 + y2 = (1 + √2)2 + (1 - √2)2
= 2[(1)2 + (√2)2]
= 2 * 3
= 6.


Question 379.
$MF#%\text{if a*b = a + b }-\sqrt{ab}\text{, then find the value of }{16*9}$MF#%
  1.    14
  2.    13
  3.    12
  4.    11
 Discuss Question
Answer: Option B. -> 13

Answer : Option B

Explanation :

$MF#%16*9 = 16 + 9 - \sqrt{16 \times 9} \\\\= 25 - \sqrt{16 \times 9} \\\\= 25 - (\sqrt{16} \times \sqrt{9} )
\\\\= 25 - ( 4 \times 3) \\\\= 25-12 = 13$MF#%


Question 380.

1.5625 = ?


  1.    1.05
  2.    1.25
  3.    1.45
  4.    1.55
 Discuss Question
Answer: Option B. -> 1.25

1|1.5625( 1.25 |1 |------- 22| 56 | 44 |------- 245| 1225 | 1225 |------- | X |-------

1.5625 = ?   1.5625 = 1.25.


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