Square and Cube Roots Quiz Set 002

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Question 1

If $2√3 + √108 = 13.86$, then what is the value of $√108 + 6√3$?

 A

20.78.

 B

20.18.

 C

20.16.

 D

20.96.

Soln.
Ans: a

The given expression can be rearranged like this: $2√3 + √{6^{2} × 3}$, which is same as $2√3 + 6√3$ which is same as $8√3 = 13.86$, from which we get $√3 = 1.73$. Next we can see that $√108 + 6√3$ is same as $√{6^{2} × 3} + 6√3$, which is same as $12√3$, which gives $12 × 1.73$ = 20.78.


Question 2

What is the value of ${√17}/6$ − $5/{√17}$?

 A

${-13√17}/102$.

 B

${+13√17}/102$.

 C

${-5√17}/102$.

 D

${+5√17}/102$.

Soln.
Ans: a

The given expression can be simplified to ${{(√17)^2} - 6 × 5}/{6 × √17}$, which is same as ${17 - 30}/{6 × √17}$, which is same as ${-13/{6 × √17}$. Rationalizing, we get ${-13/{6 × √17} × {√17/√17}$ which gives ${-13√17}/102$


Question 3

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

 A

0.

 B

16.

 C

9.

 D

1.

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 4

What is the value of ${√7}/6$ − $3/{√7}$?

 A

${-11√7}/42$.

 B

${+11√7}/42$.

 C

${-13√7}/42$.

 D

${+13√7}/42$.

Soln.
Ans: a

The given expression can be simplified to ${{(√7)^2} - 6 × 3}/{6 × √7}$, which is same as ${7 - 18}/{6 × √7}$, which is same as ${-11/{6 × √7}$. Rationalizing, we get ${-11/{6 × √7} × {√7/√7}$ which gives ${-11√7}/42$


Question 5

What is the value of ${√16/6}$ × ${5/√4}$ × ${6/√25}$?

 A

2.

 B

3.

 C

1.

 D

4.

Soln.
Ans: a

The given expression can be simplified to ${√2^4/6}$ × ${5/√2^2}$ × ${6/√5^2}$, which is same as ${2^2/6}$ × ${5/2}$ × ${6/5}$, which cancels to 2.


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Creative Commons License
This Blog Post/Article "Square and Cube Roots Quiz Set 002" 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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