Square Root and Cube Root Questions Answers

• 15. Evaluate
  $$\begin{aligned} \sqrt[3]{4\frac{12}{125}} \end{aligned}$$

  1. $$\begin{aligned} 1\frac{2}{5} \end{aligned}$$
  2. $$\begin{aligned} 1\frac{3}{5} \end{aligned}$$
  3. $$\begin{aligned} 1\frac{4}{5} \end{aligned}$$
  4. 1

  Answer And Explanation

  Answer: Option B

  Explanation:

  $$\begin{aligned} = \sqrt[3]{\frac{512}{125}} \end{aligned}$$
  $$\begin{aligned} = (\frac{8*8*8}{5*5*5})^{\frac{1}{3}} \end{aligned}$$
  
  $$\begin{aligned} = \frac{8}{5} = 1\frac{3}{5} \end{aligned}$$

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• 16. Evaluate $$\begin{aligned} \sqrt[3]{\sqrt{.000064}} \end{aligned}$$

  1. 0.0002
  2. 0.002
  3. 0.02
  4. 0.2

  Answer And Explanation

  Answer: Option D

  Explanation:

  $$\begin{aligned} = \sqrt{.000064} \end{aligned}$$
  $$\begin{aligned} = \sqrt{\frac{64}{10^6}} \end{aligned}$$
  $$\begin{aligned} = \frac{8}{10^3} = .008 \end{aligned}$$
  $$\begin{aligned} = \sqrt[3]{.008} \end{aligned}$$
  $$\begin{aligned} = \sqrt[3]{\frac{8}{1000}} \end{aligned}$$
  $$\begin{aligned} = \frac{2}{10} = 0.2 \end{aligned}$$

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• 17. The largest four digit number which is a perfect cube, is:

  1. 7000
  2. 8000
  3. 9261
  4. 9999

  Answer And Explanation

  Answer: Option C

  Explanation:

  21*21*21 = 9261

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• 18. What is the smallest number by which 3600 be divided to make it a perfect cube.

  1. 450
  2. 445
  3. 440
  4. 430

  Answer And Explanation

  Answer: Option A

  Explanation:

  $$\begin{aligned} 3600 = 2^3 \times 5^2 \times 3^2 \times 2 \end{aligned}$$
  To make it a perfect cube it must be divided by
  $$\begin{aligned} 5^2 \times 3^2 \times 2 = 450 \end{aligned}$$

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• 19. The cube root of .000216 is

  1. 0.6
  2. 0.006
  3. 0.06
  4. .0006

  Answer And Explanation

  Answer: Option C

  Explanation:

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• 20. $$\begin{aligned} \sqrt{\frac{32.4}{x}} = 2 \end{aligned}$$
  

  1. 8
  2. 8.1
  3. 9
  4. 9.1

  Answer And Explanation

  Answer: Option B

  Explanation:

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• 21. $$\begin{aligned} \sqrt{\frac{0.081 * 0.484 }{0.0064 * 6.25}} \end{aligned}$$

  1. 0.66
  2. 0.77
  3. 0.88
  4. 0.99

  Answer And Explanation

  Answer: Option D

  Explanation:

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