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NTA Abhyas JEE Main2020MathematicsStatisticsPractice

Let X n denote the mean of first n natural numbers, then the mean of X 1 , X 2 , … , X 100 is

Options

  1. A25
  2. B50
  3. C25.5
  4. D25.75

Correct answer

D. 25.75

Step-by-step solution

X n = ∑ r = 1 n r n = n n + 1 2 n = n + 1 2 ∑ n = 1 100 X n n = 100 × 101 2 + 100 200 = 101 4 + 1 2 = 25.75

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