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Bag 1 contains 4 white balls and 5 black balls, and Bag 2 contains n white balls and 3 black balls. One ball is drawn randomly from Bag 1 and transferred to Bag 2. A ball is then drawn randomly from Bag 2. If the probability, that the ball drawn is white, is 29 / 45 , then n is equal to :

Options

  1. A6
  2. B3
  3. C5
  4. D4

Correct answer

A. 6

Step-by-step solution

Bag 1 4 w, 5 B Bag 2 n w, 3 B( I ) Transferred ball is white P(w)= n+1 n+4 4 9 (II) Transferred ball is black P(w)= 5 9 n n+4 aligned & 4 n+4 9 n+36 + 5 n 9 n+36 = 29 45 & 9 n+4 9 n+36 = 29 45 n=6 aligned

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