Multiple choice

In a bag there are $6$ red, $4$ black balls. From it $2$ balls (without replacement) are drawn. If the first drawn ball is known to be red, the probability for the second drawn ball is also red is

  1. $\dfrac {5}{9}$
  2. $\dfrac {5}{18}$
  3. $\dfrac {1}{3}$
  4. $\dfrac {2}{3}$
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A Correct answer
Explanation

Initially there are 6 red and 4 black balls (total 10). If one red ball is removed, 5 red and 4 black balls remain (total 9). The probability that the second ball is red is 5/9.

AI explanation

Using the conditional probability method, the total number of balls initially is 10 and after drawing one red ball, 9 balls remain in the bag. Because 5 red balls are left, the probability of drawing a second red ball is 5 divided by 9. Therefore, the probability is 5/9.

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