The following information below can be obtained from the image;
Blue Marbles: 6
Red Marbles: 5
Yellow Marbles: 3
Total marbles = 14
The probability of an event, E, is given as:
[tex]\begin{gathered} Pr(E)\text{ = }\frac{number\text{ of favourable outomes}}{number\text{ of sample space}} \\ \text{Thus, the probability of of choosing a blue marble is;} \\ Pr(\text{choosing a blue marble)=}\frac{number\text{ of blue marbles}}{number\text{ of total marbles}} \\ Pr(choo\sin g\text{ a blue marble) = }\frac{6}{14} \\ \text{In simplified form;} \\ Pr(\text{choosing a blue marble)=}\frac{3}{7} \end{gathered}[/tex]Hence, the number that belongs in the green box is 3