A bag contains 3 pink marbles, 2 red marbles, 5 blue marbles, 3 orange marbles, 4 black marbles, and 2 green marbles. If 2 marbles are selected, what is the probability of picking 2 orange marbles?

There are LaTeX: \displaystyle C(19,2)=171 to select 2 marbles. There are LaTeX: \displaystyle 3 ways to select 2 orange from 3 orange. This gives the probability LaTeX: \displaystyle \frac{1}{57}