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An urn contains 5 red and 2 green balls. A ball is drawn at random from the urn. If the drawn ball is green, then a red ball is added to the urn and if the drawn ball is red, then a green ball is added to the urn; the original ball is not returned to the urn. Now, a second ball is drawn at random from it. The probability that the second ball is red, is:

Options

  1. A21 49
  2. B26 49
  3. C32 49
  4. D27 49

Correct answer

C. 32 49

Step-by-step solution

Let A is event that 2 n d drawn ball is red. ∴ P A = P R × P A / R + P G × P   A / G = 5 7 × 4 7 + 2 7 × 6 7 = 32 49

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