New Enroll in RBI Grade B New Batch - Starts on May 21

    Question

    Difference between a number and its square root is 42.

    Find the number.
    A 36 Correct Answer Incorrect Answer
    B 64 Correct Answer Incorrect Answer
    C 25 Correct Answer Incorrect Answer
    D 49 Correct Answer Incorrect Answer

    Solution

    Let the number be 'x'.So, x - 42 = √xOn, squaring both sides, we have;(x - 42) 2 = (√x) 2Or, x2 + 1764 - 84x = xOr, x2 - 85x + 1764 = 0Or, x2 - 36x - 49x + 1764 = 0Or, x(x - 36) - 49(x - 36) = 0Or, (x - 49) (x - 36) = 0So, x = 49 or x = 36We can see that 'x' = 36 will not satisfy the equation, so x = 49

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