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A box contains 15 green and 10 yellow balls. If 10 balls are randomly drawn, one-by-one, with replacement, then the variance of the number of green balls drawn is:

Options

  1. A12 5
  2. B6
  3. C4
  4. D6 25

Correct answer

A. 12 5

Step-by-step solution

For Bernoulli's trials Variance = n . p . q Given, number of trials n = 10 Probability of drawing a green ball p = 15 25 = 3 5 and q = 2 5 Hence, Variance = 10 × 3 5 × 2 5 = 12 5

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