Square and Cube Roots Quiz Set 019

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Question 1

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 2

What is √(9720) × √(30)?

 A

540.

 B

450.

 C

496.

 D

196.

Soln.
Ans: a

We can see that √(9720) × √(30) is same as √(2 × 2 × 2 × 3 × 3 × 3 × 3 × 3 × 5 ) × √(2 × 3 × 5 ) which equals √(24 × 36 × 52), which equals (22 × 33 × 51), which gives 540.


Question 3

What is √0.0064?

 A

0.08.

 B

0.16.

 C

0.016.

 D

0.8.

Soln.
Ans: a

We can see that 0.08 × 0.08 = 0.0064, so square root is 0.08.


Question 4

How many 2 digit numbers are their whose squares end in 8?

 A

0.

 B

11.

 C

10.

 D

5.

Soln.
Ans: a

It is not possible for the square of any number to end in 2, 3, 7 or 8. Hence the answer is 0.


Question 5

If x = 0.3193, then what is the value of $11x + √{16x^2 - 8x + 1}$?

 A

3.24.

 B

0.324.

 C

32.4.

 D

3.16.

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 = 3.24.


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Creative Commons License
This Blog Post/Article "Square and Cube Roots Quiz Set 019" by Parveen (Hoven) is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
Updated on 2017-04-07.

Posted by Parveen(Hoven),
Aptitude Trainer


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