Square and Cube Roots Quiz Set 017

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Question 1

What is √(4320) × √(4320)?

 A

4320.

 B

4400.

 C

4416.

 D

4520.

Soln.
Ans: a

We can see that √(4320) × √(4320) is same as √(2 × 2 × 2 × 2 × 2 × 3 × 3 × 3 × 5 ) × √(2 × 2 × 2 × 2 × 2 × 3 × 3 × 3 × 5 ) which equals √(210 × 36 × 52), which equals (25 × 33 × 51), which gives 4320.


Question 2

If $√2$ = 1.41, then what is the value of ${√2}/5$ − $13/{√2}$ + $√8$?

 A

-6.081.

 B

+6.081.

 C

-6.009.

 D

+6.009.

Soln.
Ans: a

The given expression can be simplified to ${{(√2)^2} - {5 × 13} + {5 × √2 × √{2 × 2^2}}}/{5 × √2}$, which is same as ${2 - 65 + 20}/{5 × √2}$, which is same as ${-43/{5 × √2}$. Rationalizing, we get ${-43/{5 × √2} × {√2/√2}$ which gives ${-43√2}/10$ which = -6.081.


Question 3

What is the value of ${√5}/3$ − $2/{√5}$?

 A

${-1√5}/15$.

 B

${+1√5}/15$.

 C

${-2√5}/15$.

 D

${+2√5}/15$.

Soln.
Ans: a

The given expression can be simplified to ${{(√5)^2} - 3 × 2}/{3 × √5}$, which is same as ${5 - 6}/{3 × √5}$, which is same as ${-1/{3 × √5}$. Rationalizing, we get ${-1/{3 × √5} × {√5/√5}$ which gives ${-1√5}/15$


Question 4

What is √0.0036?

 A

0.06.

 B

0.36.

 C

0.12.

 D

0.09.

Soln.
Ans: a

We can see that 0.06 × 0.06 = 0.0036, so square root is 0.06.


Question 5

If x = 0.7342, then what is the value of $11x + √{16x^2 - 8x + 1}$?

 A

6.14.

 B

12.28.

 C

3.14.

 D

3.07.

Soln.
Ans: a

By inspection, $11x + √{16x^2 - 8x + 1}$ is same as $11x + √{({1 - 4x})^2}$, which is same as 11x + (1 - 4x) = 1 + 7x = 6.14.


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This Blog Post/Article "Square and Cube Roots Quiz Set 017" by Parveen (Hoven) is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
Updated on 2017-05-17.

Posted by Parveen(Hoven),
Aptitude Trainer


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