A hat contains 2 red marbles, 3 blue marbles, and 4 green marbles. You choose two different marbles at random. What is the probability that they are the same color?
\(\mathcal P(\text{same color}) = \dfrac29\cdot\dfrac18 + \dfrac39\cdot \dfrac28 + \dfrac49\cdot\dfrac38 = \dfrac5{18}\)
