Square and Cube Roots Quiz Set 007

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Question 1

What is cube root of 0.000729?

 A

0.09.

 B

0.729.

 C

0.81.

 D

0.081.

Soln.
Ans: a

We can see that 0.09 × 0.09 × 0.09 = 0.000729, so cube root is 0.09.


Question 2

What is the value of $(√9 - 1/√9)^2$?

 A

$7{1/9}$.

 B

$7{2/3}$.

 C

$7{6/11}$.

 D

$7{11/81}$.

Soln.
Ans: a

I will give a general solution for any n. $(√n - 1/√n)^2$ is same as $({(√n)^2 - 1}/√n)^2$ which becomes $(n - 1)^2/n$. Putting n = 9, we get ${64/9}$, which is same as: $7{1/9}$.


Question 3

What is the value of ${√17}/3$ − $2/{√17}$?

 A

${11√17}/51$.

 B

${-11√17}/51$.

 C

${9√17}/51$.

 D

${-9√17}/51$.

Soln.
Ans: a

The given expression can be simplified to ${{(√17)^2} - 3 × 2}/{3 × √17}$, which is same as ${17 - 6}/{3 × √17}$, which is same as ${11/{3 × √17}$. Rationalizing, we get ${11/{3 × √17} × {√17/√17}$ which gives ${11√17}/51$


Question 4

What is the least number that should be subtracted from 0.0509 to make it a perfect square?

 A

0.05.

 B

0.06.

 C

0.02.

 D

0.03.

Soln.
Ans: a

We know that 0.03 = $√0.0009$, so by inspection we can see that 0.0509 - 0.05 will give us 0.0009.


Question 5

What is √0.0009?

 A

0.03.

 B

0.9.

 C

0.3.

 D

0.81.

Soln.
Ans: a

We can see that 0.03 × 0.03 = 0.0009, so square root is 0.03.


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Creative Commons License
This Blog Post/Article "Square and Cube Roots Quiz Set 007" 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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