Multiple choice

Passage

(Direction 178-179): Study the given information carefully and answer the questions that follow- A box contains 4 blue, 5 green and 3 red balls.

If three balls are picked at random, what is the probability that either all are red or all are blue?

  1. a) 1/44

  2. b) 1/28

  3. c) 2/55

  4. d) 1/66

  5. e) 3/8
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Total balls = 4+5+3 = 12. Ways to pick 3 balls = 12C3 = 220. Ways to pick 3 red = 3C3 = 1. Ways to pick 3 blue = 4C3 = 4. Total favorable = 1+4 = 5. Probability = 5/220 = 1/44.

AI explanation

Using the addition rule of probability for mutually exclusive events, the probability is (3C3)/(12C3) plus (4C3)/(12C3). The calculation becomes 1/220 plus 4/220, which equals 5/220. Simplifying the fraction 5/220 gives the result of 1/44.

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