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

There are LaTeX: \displaystyle C(13,2)=78 to select 2 marbles. There are LaTeX: \displaystyle 3 ways to select 2 green from 3 green. This gives the probability LaTeX: \displaystyle \frac{1}{26}