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Question: Answered & Verified by Expert
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:
MathematicsProbabilityJEE MainJEE Main 2019 (09 Jan Shift 2)
Options:
  • A 2149
  • B 2649
  • C 3249
  • D 2749
Solution:
2170 Upvotes Verified Answer
The correct answer is: 3249
Let A is event that 2nd drawn ball is red.

PA=PR×PA/R+PG×P A/G

=57×47+27×67

=3249

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