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      Question

      A number exceeds its square root by 30. What is the

      number?
      A 10 Correct Answer Incorrect Answer
      B 25 Correct Answer Incorrect Answer
      C 36 Correct Answer Incorrect Answer
      D 45 Correct Answer Incorrect Answer

      Solution

      ATQ,

      Let the number be 'x'.

      So, x - √x = 30

      On squaring both sides, we get:

      (x - √x)² = 30²

      ⇒ x² + x - 2x√x = 900

      Now, let’s simplify:

      (x - 30)² = x

      ⇒ x² - 60x + 900 = x

      ⇒ x² - 61x + 900 = 0

      ⇒ x² - 25x - 36x + 900 = 0

      ⇒ x(x - 25) - 36(x - 25) = 0

      ⇒ (x - 36)(x - 25) = 0

      So, x = 36 or x = 25

      Only x = 36 satisfies the original equation

      Hence, the number is 36

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