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Square Root and Cube Root Questions Answers

  • 8. \begin{aligned}
    (\frac{\sqrt{625}}{11} \times \frac{14}{\sqrt{25}} \times \frac{11}{\sqrt{196}})
    \end{aligned}

    1. 15
    2. 7
    3. 5
    4. 9
    Answer And Explanation

    Answer: Option C

    Explanation:

    \begin{aligned}
    = (\frac{25}{11} \times \frac{14}{5} \times \frac{11}{14})
    \end{aligned}

    \begin{aligned}
    = 5
    \end{aligned}

  • 9. Find the value of x
    \begin{aligned}
    \frac{2707}{\sqrt{x}} = 27.07
    \end{aligned}

    1. 1000
    2. 10000
    3. 10000000
    4. None of above
    Answer And Explanation

    Answer: Option B

    Explanation:

    \begin{aligned}
    = \frac{2707}{27.07} = \sqrt{x}
    \end{aligned}

    \begin{aligned}
    => \frac{2707 \times 100}{2707} = \sqrt{x}
    \end{aligned}

    \begin{aligned}
    => 100 = \sqrt{x}
    \end{aligned}

    \begin{aligned}
    => x = 100^2 = 10000
    \end{aligned}

  • 10. What is the square root of 0.16

    1. 0.4
    2. 0.04
    3. 0.004
    4. 4
    Answer And Explanation

    Answer: Option A

    Explanation:

    as .4 * .4 = 0.16

  • 11. The least perfect square, which is divisible by each of 21, 36 and 66 is

    1. 213414
    2. 213424
    3. 213434
    4. 213444
    Answer And Explanation

    Answer: Option D

    Explanation:

    L.C.M. of 21, 36, 66 = 2772

    Now, 2772 = 2 x 2 x 3 x 3 x 7 x 11

    To make it a perfect square, it must be multiplied by 7 x 11.

    So, required number = 2 x 2 x 3 x 3 x 7 x 7 x 11 x 11 = 213444

  • 12. Evaluate
    \begin{aligned}
    \sqrt{0.00059049}
    \end{aligned}

    1. 0.00243
    2. 0.0243
    3. 0.243
    4. 2.43
    Answer And Explanation

    Answer: Option B

    Explanation:

    Very obvious tip here is, after squre root the terms after decimal will be half (that is just a trick), works awesome at many questions like this.

  • 13. if a = 0.1039, then the value of
    \begin{aligned} \sqrt{4a^2 - 4a + 1} + 3a \end{aligned}

    1. 12.039
    2. 1.2039
    3. 11.039
    4. 1.1039
    Answer And Explanation

    Answer: Option D

    Explanation:

    Tip: Please check the question carefully before answering. As 3a is not under the root we can convert it into a formula , lets evaluate now :

    \begin{aligned}
    = \sqrt{4a^2 - 4a + 1} + 3a \end{aligned}

    \begin{aligned}
    = \sqrt{(1)^2 + (2a)^2 - 2x1x2a} + 3a \end{aligned}

    \begin{aligned}
    = \sqrt{(1-2a)^2} + 3a \end{aligned}

    \begin{aligned}
    = (1-2a) + 3a \end{aligned}

    \begin{aligned}
    = (1-2a) + 3a \end{aligned}

    \begin{aligned}
    = 1 + a = 1 + 0.1039 = 1.1039 \end{aligned}



  • 14. Find the value of X
    \begin{aligned} \sqrt{81} + \sqrt{0.81} = 10.09 - X \end{aligned}

    1. 0.019
    2. 0.19
    3. 0.9
    4. 0.109
    Answer And Explanation

    Answer: Option B

    Explanation:

    \begin{aligned}
    => \sqrt{81} + \sqrt{0.81} = 10.09 - X
    \end{aligned}

    \begin{aligned}
    => 9 + 0.9 = 10.09 - X
    \end{aligned}

    \begin{aligned}
    => X = 10.09 - 9.9 = 0.19
    \end{aligned}

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