Multiple choice

A bag contains $3$ black, $4$ white and $5$ red balls. One ball is drawn at random. Find the probability that it is either a black ball or red ball.

  1. $\dfrac {2}{3}$
  2. $\dfrac {5}{12}$
  3. $\dfrac {1}{12}$
  4. $\dfrac {1}{2}$
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A Correct answer
Explanation

Total balls = 3 + 4 + 5 = 12. Favorable outcomes (black or red) = 3 + 5 = 8. Probability = 8/12 = 2/3.

AI explanation

The total number of balls is 3 + 4 + 5 = 12. Using the addition rule of probability for mutually exclusive events, the probability of drawing either a black or red ball is (3/12) + (5/12). This simplifies to 8/12, which equals 2/3.

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