SSC CGL (Prelims) General: Probability questions with solutions

Q1. A box has 4 red, 5 blue, and 6 green balls. What is the probability of drawing a non-blue ball?

1. 4/15
2. 9/15
3. 10/15
4. 6/15

Answer: 10/15

Total balls = 4 + 5 + 6 = 15. Non-blue balls = red + green = 4 + 6 = 10, so the probability is 10/15.

Q2. A box contains 4 red, 5 blue, and 6 green balls. If one ball is drawn at random, what is the probability that it is not blue?

1. 4/15
2. 9/15
3. 10/15
4. 6/15

Answer: 10/15

Total balls = 4 + 5 + 6 = 15. Balls that are not blue = 4 + 6 = 10. So the probability is $\frac{10}{15}$.