Let:
• A ,be the event of getting a red marble
,• B ,be the event of getting a green marble
,• C ,be the event of getting a blue marble
We'll have that:
[tex]\begin{gathered} P(A)=\frac{8}{36} \\ \\ P(B)=\frac{6}{36} \\ \\ P(C)=\frac{12}{36} \end{gathered}[/tex]