Multiple choice

A bag have 5 red,4 green and 3 black balls if 3 ball are drawn at random, then what is the probability that all the 3balls are Red or 1 ball is Black and the remaining 2 are Green ?

  1. 7/55

  2. 5/8

  3. 3/7

  4. 17/24

  5. 21/55

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Total balls = 5 + 4 + 3 = 12. Probability of 3 red: (5/12) × (4/11) × (3/10) = 60/1320 = 1/22. Probability of 1 black + 2 green: 3 ways to arrange BGG, so 3 × (3/12) × (4/11) × (3/10) = 108/1320 = 9/110. Combined probability: 1/22 + 9/110 = 5/110 + 9/110 = 14/110 = 7/55.