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Quantitative Aptitude

SQUARE ROOT AND CUBE ROOT MCQs

Square Roots, Cube Roots, Squares And Square Roots

Total Questions : 547 | Page 40 of 55 pages
Question 391.

If 35 + 125 = 17.88, then what will be the value of 80 + 65 ?


  1.    13.41
  2.    20.46
  3.    21.66
  4.    22.35
 Discuss Question
Answer: Option D. -> 22.35

35 + 125 = 17.88

 If 35 + 125 = 17.88, Then What Will Be The Value Of 80 + 65... 35 + 25 x 5 = 17.88

 If 35 + 125 = 17.88, Then What Will Be The Value Of 80 + 65... 35 + 55 = 17.88

 If 35 + 125 = 17.88, Then What Will Be The Value Of 80 + 65... 85 = 17.88

 If 35 + 125 = 17.88, Then What Will Be The Value Of 80 + 65... 5 = 2.235

 If 35 + 125 = 17.88, Then What Will Be The Value Of 80 + 65... 80 + 65 = 16 x 5 + 65

   = 45 + 65

   = 105 = (10 x 2.235) = 22.35


Question 392.

If a = 0.1039, then the value of 4a2 - 4a + 1 + 3a is:


  1.    0.1039
  2.    0.2078
  3.    1.1039
  4.    2.1039
 Discuss Question
Answer: Option C. -> 1.1039

4a2 - 4a + 1 + 3a = (1)2 + (2a)2 - 2 x 1 x 2a + 3a

   = (1 - 2a)2 + 3a

   = (1 - 2a) + 3a

   = (1 + a)

   = (1 + 0.1039)

   = 1.1039


Question 393.
$MF#%\text{What is the difference between }(\sqrt{18}+\sqrt{3})\text{ and }(2+\sqrt{12})$MF#%
  1.    3√2 - 2√3
  2.    âˆš2 - 2√3
  3.    2√2 - √3
  4.    2√2 + √3
 Discuss Question
Answer: Option C. -> 2√2 - √3

Answer : Option C

Explanation :

$MF#%\text{Difference = }(\sqrt{18}+\sqrt{3}) - (\sqrt{2}+\sqrt{12})\\\
= (\sqrt{2 \times 9}+\sqrt{3}) - (\sqrt{2}+\sqrt{3 \times 4})\\\\
= (3\sqrt{2}+\sqrt{3}) - (\sqrt{2}+2\sqrt{3}) \\\\
= 3\sqrt{2}+\sqrt{3} -\sqrt{2} - 2\sqrt{3}\\\\
= 2\sqrt{2} - \sqrt{3}$MF#%


Question 394.
$MF#%\sqrt[3]{4\dfrac{12}{125}}\text{ = ?}$MF#%
  1.    1
  2.    $MF#%1\dfrac{2}{5}$MF#%
  3.    $MF#%1\dfrac{3}{5}$MF#%
  4.    $MF#%1\dfrac{4}{5}$MF#%
 Discuss Question
Answer: Option C. -> $MF#%1\dfrac{3}{5}$MF#%

Answer : Option C

Explanation :

$MF#%\sqrt[3]{4\dfrac{12}{125}}=\sqrt[3]{\dfrac{512}{125}} = \sqrt[3]{\dfrac{2\times 2 \times 2 \times 2\times 2 \times 2 \times 2\times 2 \times 2}{5 \times 5 \times 5}} =\dfrac{2\times 2 \times 2 }{5} = \dfrac{8}{5} = 1\dfrac{3}{5}$MF#%


Question 395.
$MF#%\text{If }\dfrac{x}{\sqrt{512}} = \dfrac{\sqrt{648}}{x}\text{, find the value of }x.$MF#%
  1.    24
  2.    12
  3.    48
  4.    36
 Discuss Question
Answer: Option A. -> 24

Answer : Option A

Explanation :

$MF#%\dfrac{x}{\sqrt{512}} = \dfrac{\sqrt{648}}{x}\\\\
\Rightarrow x^2 = \sqrt{512} \times \sqrt{648} = \sqrt{512 \times 648}
= \sqrt{2 \times 2 \times 2 \times 64 \times 2 \times 2 \times 2 \times 81 } = 2\times 2 \times 2 \times 8 \times 9 \\\\
x = \sqrt{2\times 2 \times 2 \times 8 \times 9} = 2 \times 4 \times 3 = 24$MF#%


Question 396.
By what least number 675 be multiplied to obtain a number which is a perfect cube?



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

To make it a perfect cube, it must be multiplied by 5.


Question 397.
$MF#%\text{What is the square root of }\left(8+2\sqrt{15}\right)?$MF#%
  1.    2√5 + 2√3
  2.    âˆš5 + √3
  3.    âˆš2 + √6
  4.    2√2 + 2√6
 Discuss Question
Answer: Option B. -> √5 + √3

Answer : Option B

Explanation :

$MF#%8+2\sqrt{15}= 5+3 + 2 \times\sqrt{5} \times \sqrt{3}
\\\\=(\sqrt{5})^2+(\sqrt{3})^2 + (2 \times\sqrt{5} \times \sqrt{3})
\\\\= (\sqrt{5} +\sqrt{3} )^2$MF#%

$MF#%\text{Hence, }\sqrt{\left(8+2\sqrt{15}\right)} = \sqrt{(\sqrt{5} +\sqrt{3} )^2} = \sqrt{5} +\sqrt{3} $MF#%


Question 398.
If x = (√5+√3) / (√5-√3) and y = (√5-√3) / (√5+√3), find the value of (x2+y2).



  1.    52
  2.    61
  3.    62
  4.    60
 Discuss Question
Answer: Option C. -> 62


Question 399.
$MF#%\sqrt{248 + \sqrt{64}}\text{} = ?$MF#%
  1.    21
  2.    14
  3.    12
  4.    16
 Discuss Question
Answer: Option D. -> 16

Answer : Option D

Explanation :

$MF#%\sqrt{248 + \sqrt{64}} = \sqrt{248 +8} = \sqrt{256} = 16$MF#%


Question 400.
$MF#%\text{if a = 0.2917, then the value of }\sqrt{4a^2 - 4a + 1} + 3a\text{ is :}$MF#%
  1.    0.5834
  2.    0.2917
  3.    1.2917
  4.    2.2917
 Discuss Question
Answer: Option C. -> 1.2917

Answer : Option C

Explanation :

$MF#%\sqrt{4a^2 - 4a + 1 } + 3a = \sqrt{(1)^2 - 2 \times 1 \times 2a + (2a)^2} + 3a = \sqrt{\left(1 -2a\right)^2}+ 3a \\\\= 1 - 2a + 3a = 1 + a\\\\
=1 + 0.2917 = 1.2917$MF#%


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