The total count of balls is \( 5 + 3 + 2 = 10 \). The combinations for selecting 2 balls from 10 are \( \binom{10}{2} = 45 \). The combinations for selecting 2 red balls from the 5 available red balls are \( \binom{5}{2} = 10 \). Therefore, the probability of selecting two red balls is \( \frac{10}{45} = \frac{1}{6} \). The confirmed result is \( \boxed{\frac{1}{6}} \).