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    Question

    A number exceeds 40 times its reciprocal by 7/8. Determine

    the number.
    A 5 Correct Answer Incorrect Answer
    B 10 Correct Answer Incorrect Answer
    C 12 Correct Answer Incorrect Answer
    D 18 Correct Answer Incorrect Answer

    Solution

    ATQ,

    Let the number be x.

    x – 40/x = 7/8

    ⇒ (x² – 40)/x = 7/8

    Cross-multiplying:

    8x² – 320 = 7x

    ⇒ 8x² – 7x – 320 = 0

    Factorizing:

    8x² – 40x + 33x – 320 = 0

    8x(x – 5) + 64(x – 5) = 0

    (8x + 64)(x – 5) = 0

    So, x = –8 or x = 5

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