# Square and Cube Roots Quiz Set 007

### Question 1

What is cube root of 0.000729?

A

0.09.

B

0.729.

C

0.81.

D

0.081.

Soln.
Ans: a

We can see that 0.09 × 0.09 × 0.09 = 0.000729, so cube root is 0.09.

### Question 2

What is the value of \$(√9 - 1/√9)^2\$?

A

\$7{1/9}\$.

B

\$7{2/3}\$.

C

\$7{6/11}\$.

D

\$7{11/81}\$.

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 = 9, we get \${64/9}\$, which is same as: \$7{1/9}\$.

### Question 3

What is the value of \${√17}/3\$ − \$2/{√17}\$?

A

\${11√17}/51\$.

B

\${-11√17}/51\$.

C

\${9√17}/51\$.

D

\${-9√17}/51\$.

Soln.
Ans: a

The given expression can be simplified to \${{(√17)^2} - 3 × 2}/{3 × √17}\$, which is same as \${17 - 6}/{3 × √17}\$, which is same as \${11/{3 × √17}\$. Rationalizing, we get \${11/{3 × √17} × {√17/√17}\$ which gives \${11√17}/51\$

### Question 4

What is the least number that should be subtracted from 0.0509 to make it a perfect square?

A

0.05.

B

0.06.

C

0.02.

D

0.03.

Soln.
Ans: a

We know that 0.03 = \$√0.0009\$, so by inspection we can see that 0.0509 - 0.05 will give us 0.0009.

### Question 5

What is √0.0009?

A

0.03.

B

0.9.

C

0.3.

D

0.81.

Soln.
Ans: a

We can see that 0.03 × 0.03 = 0.0009, so square root is 0.03.

This Blog Post/Article "Square and Cube Roots Quiz Set 007" 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