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

There are LaTeX: \displaystyle C(16,2)=120 to select 2 marbles. There are LaTeX: \displaystyle 1 ways to select 2 pink from 2 pink. This gives the probability LaTeX: \displaystyle \frac{1}{120}