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    Find the value of p so that the expression (15.97)³ + 1.4373 × p + (0.03)³ is a perfect cube.
    Question

    Find the value of p so that the expression (15.97)³ + 1.4373 × p + (0.03)³ is a perfect cube.

    A.

    0.000027

    B.

    4096

    C.

    16

    D.

    47.91

    Correct option is C

    Given:

    Expression: (15.97)3+1.4373×p+(0.03)3(15.97)^3 + 1.4373×p + (0.03)^3​​

    Need value of (p) so the entire expression becomes a perfect cube

    Concept Used:

    Binomial identity for cubes:

    (ab)3=a33a2b+3ab2b3(a - b)^3 = a^3 - 3a^2b + 3ab^2 - b^3​​

    Solution: 

    Here, 15.97 = 16 - 0.03, so a = 16, b = 0.03

    (160.03)3+(0.03)3 =1633(16)2(0.03)+3(16)(0.03)2 =409623.04+0.0432 =4073.0032(16 - 0.03)^3 + (0.03)^3 \\ \ \\ = 16^3 - 3(16)^2(0.03) + 3(16)(0.03)^2 \\ \ \\ = 4096 - 23.04 + 0.0432 \\ \ \\ = 4073.0032​​

    Perfect cube condition: (15.97)3+(0.03)3+1.4373p=163(15.97)^3 + (0.03)^3 + 1.4373p = 16^3​​

    Now, 

    4073.0032 + 1.4373p = 4096

    1.4373p = 22.9968

    p = 22.99681.4373 \frac{22.9968}{1.4373}​ = 16

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