Given 6 red balls and 4 blue balls, with a total of 10 balls:
- The probability of selecting all 6 red balls is the ratio of the ways to select 6 red balls to the total ways to select 6 balls from 10.
- Favorable outcomes: Selecting all 6 red balls = 1 way
- Total possible outcomes: Selecting any 6 balls from 10 = \( \binom{10}{6} = 210 \)
So, the probability is \( \frac{1}{210} \).