Square and Cube Roots Quiz Set 011

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Question 1

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 2

One-fourth of the square-root of which number is 0.9?

 A

12.96.

 B

12.56.

 C

9.25.

 D

9.50.

Soln.
Ans: a

Let the number be n. So ${1/4} × √n$ = 0.9, which gives $√n$ = 4 × 0.9 = 3.6. so n = $3.6^2$ = 12.96.


Question 3

Each book of a shelf has as many pages as is the total number of books in that shelf. If there are 169 pages in all, how many books are there?

 A

13.

 B

16.

 C

24.

 D

9.

Soln.
Ans: a

Let the number of books = n. So pages in one book are also n, and therefore, pages in n books = $n^2$. We have been given $n^2 = 169$, which gives n = 13.


Question 4

What is the value of $(√4 - 1/√4)^2$?

 A

$2{1/4}$.

 B

$2{3/4}$.

 C

$2{1/3}$.

 D

$2{1/6}$.

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 = 4, we get ${9/4}$, which is same as: $2{1/4}$.


Question 5

What is the value of $√{(13 - 5√5) × (13 + 5√5)}$?

 A

$√44$.

 B

$√25$.

 C

$√5$.

 D

$√65$.

Soln.
Ans: a

By inspection, we can easily see that the formula (a - b) × (a + b) can be used to simplify like this: $√{(13)^2 - (5√5)^2}$, which is same as $√{169 - (5^2 × 5)}$, which is same as $√{169 - 125}$ = $√44$.


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This Blog Post/Article "Square and Cube Roots Quiz Set 011" by Parveen (Hoven) is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
Updated on 2017-10-26.

Posted by Parveen(Hoven),
Aptitude Trainer


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