To solve this problem, you can use the following formula:
[tex]P(A)=\frac{outcome\text{ in A}}{total\text{ number of outcomes}}.[/tex]
Now, for all the problems, the total number of outcomes is:
[tex]8+10+18=36.[/tex]
Now, there are 8 white marbles and 10 blue marbles, therefore:
[tex]P(white\text{ or blue\rparen= }\frac{8+10}{36}=\frac{18}{36}=\frac{1}{2}.[/tex]
Analogously:
[tex]P(white\text{ or red\rparen=}\frac{8+18}{36}=\frac{26}{36}=\frac{13}{18}.[/tex][tex]P(blue\text{ or red\rparen=}\frac{10+18}{36}=\frac{7}{9}.[/tex]
Answer:
1.-
[tex]\frac{1}{2}.[/tex]
2.-
[tex]\frac{13}{18}.[/tex]
3.-
[tex]\frac{7}{9}.[/tex]
