Multiple choice

. In a bag there are 3 magenta balls, 5 green balls and 7 blue balls . 2 balls are drawn one by one without replacement. If the first ball comes out to be of magenta colour, then 8 more magenta coloured balls are added to bag. Find the probability that both the balls drawn are of magenta colour.

  1. 1/11

  2. 2/11

  3. 3/23

  4. 4/23

  5. 6/11
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A Correct answer
Explanation

Initial: 3M, 5G, 7B (Total 15). First ball is M: P(M1) = 3/15. Remaining: 2M, 5G, 7B. Add 8M: 10M, 5G, 7B (Total 22). P(M2|M1) = 10/22 = 5/11. P(M1 and M2) = (3/15) * (5/11) = (1/5) * (5/11) = 1/11.

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