NDA Math Mock Test 02 – Question 112

Question:

If \(\bar{x}\) is the mean of \(x_1, x_2, \ldots, x_n\), then for a * 0, then the mean of \(ax_1, ax_2, \ldots, ax_n, \dfrac{x_1}{a}, \dfrac{x_2}{a}, \ldots, \dfrac{x_n}{a}\) is ________.

यदि \(\bar{x}\), \(x_1, x_2, \ldots, x_n\) का माध्य है, तो \(a \neq 0\) के लिए, \(ax_1, ax_2, \ldots, ax_n, \dfrac{x_1}{a}, \dfrac{x_2}{a}, \ldots, \dfrac{x_n}{a}\) का माध्य ________ है।

Options:

  • \(\left(a + \dfrac{1}{a}\right)\dfrac{\bar{x}}{2}\)
  • \(\dfrac{\left(a + \dfrac{1}{a}\right)\bar{x}}{2n}\)
  • \(\left(a + \dfrac{1}{a}\right)\bar{x}\)
  • \(\left(a + \dfrac{1}{a}\right)\dfrac{\bar{x}}{n}\)
  • \(\left(a + \dfrac{1}{a}\right)\dfrac{\bar{x}}{2}\)
  • \(\dfrac{\left(a + \dfrac{1}{a}\right)\bar{x}}{2n}\)
  • \(\left(a + \dfrac{1}{a}\right)\bar{x}\)
  • \(\left(a + \dfrac{1}{a}\right)\dfrac{\bar{x}}{n}\)

Correct Answer: a)

Explanation:

Sum of all \(2n\) terms \(= a\sum x_i + \dfrac{1}{a}\sum x_i = \left(a + \dfrac{1}{a}\right)n\bar{x}\).
Mean \(= \dfrac{(a + 1/a)n\bar{x}}{2n} = \left(a + \dfrac{1}{a}\right)\dfrac{\bar{x}}{2}\).

सभी \(2n\) पदों का योग \(= \left(a + \dfrac{1}{a}\right)n\bar{x}\)।
माध्य \(= \dfrac{(a + 1/a)n\bar{x}}{2n} = \left(a + \dfrac{1}{a}\right)\dfrac{\bar{x}}{2}\)।

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