# Square and Cube Roots Quiz Set 002

### 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.

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 2017-05-17.

Posted by Parveen(Hoven),
Aptitude Trainer