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NTA Abhyas JEE Main2020MathematicsStatisticsPractice

If the standard deviation of the numbers 2 , 4 , a and 10 is 3.5 , then which of the following is true?

Options

  1. A3 a 2 - 23 a + 24 = 0
  2. B3 a 2 - 26 a + 46 = 0
  3. C3 a 2 - 32 a + 28 = 0
  4. D3 a 2 - 34 a + 45 = 0

Correct answer

C. 3 a 2 - 32 a + 28 = 0

Step-by-step solution

S.D. = ∑ x i 2 n - ∑ x i n 2 ∴ 49 4 = 4 + 16 + a 2 + 100 4 - 16 + a 4 2 ⇒ 3 a 2 - 32 a + 28 = 0

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