A box contains 6 red, 4 white and 5 black balls. A person draws 4 balls from the box at random. Find the probability that among the balls drawn there is atleast one ball of each colour.

Explanation

To solve the problem of finding the probability that among the 4 balls drawn from a box containing 6 red, 4 white, and 5 black balls, there is at least one ball of each color, we can use the complementary approach.

### Step-by-Step Solution:

1. **Identify Total Balls and Total Outcomes**:
- Total number of balls = 6 (red) + 4 (white) + 5 (black) = 15 balls.
- Total ways to choose 4 balls from 15 = \( \binom{15}{4} \).

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