Square and Cube Roots Quiz Set 014

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Question 1

One-fourth of the square-root of which number is 0.6?

 A

5.76.

 B

.5.24

 C

5.96.

 D

5.49.

Soln.
Ans: a

Let the number be n. So ${1/4} × √n$ = 0.6, which gives $√n$ = 4 × 0.6 = 2.4. so n = $2.4^2$ = 5.76.


Question 2

What is √0.0004?

 A

0.02.

 B

0.4.

 C

0.2.

 D

0.002.

Soln.
Ans: a

We can see that 0.02 × 0.02 = 0.0004, so square root is 0.02.


Question 3

What is the value of $(√5 - 1/√5)^2$?

 A

$3{1/5}$.

 B

$3{2/5}$.

 C

$3{3/5}$.

 D

$3{4/5}$.

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 = 5, we get ${16/5}$, which is same as: $3{1/5}$.


Question 4

What is √(480) × √(1080)?

 A

720.

 B

240.

 C

360.

 D

120.

Soln.
Ans: a

We can see that √(480) × √(1080) is same as √(2 × 2 × 2 × 2 × 2 × 3 × 5 ) × √(2 × 2 × 2 × 3 × 3 × 3 × 5 ) which equals √(28 × 34 × 52), which equals (24 × 32 × 51), which gives 720.


Question 5

What is the least number that should be subtracted from 0.0864 to make it a perfect square?

 A

0.08.

 B

0.07.

 C

0.06.

 D

0.09.

Soln.
Ans: a

We know that 0.08 = $√0.0064$, so by inspection we can see that 0.0864 - 0.08 will give us 0.0064.


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Creative Commons License
This Blog Post/Article "Square and Cube Roots Quiz Set 014" by Parveen (Hoven) is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
Updated on 2019-08-18.

Posted by Parveen(Hoven),
Aptitude Trainer


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