Answer:
The total number of marbles in the bag is
[tex]\begin{gathered} n(B)=5 \\ n(R)=2 \\ n(G)=3 \end{gathered}[/tex]The total number of marbles will be
[tex]\begin{gathered} n(S)=n(R)+n(B)+n(G) \\ n(S)=2+5+3 \\ n(S)=10 \end{gathered}[/tex]Concept :
To calculate the probability of selecting not a marble, we will use the formula below
[tex]Pr(\text{not red)=1 -Pr(R)}[/tex][tex]\begin{gathered} Pr(R)=\frac{n(R)}{n(S)} \\ Pr(R)=\frac{2}{10} \end{gathered}[/tex]Hence,
The probability os selecting not red will be
[tex]\begin{gathered} Pr(\text{not red)=1 -Pr(R)} \\ Pr(\text{not red)}=1-\frac{2}{10} \\ Pr(\text{not red)=}\frac{10-2}{10} \\ Pr(\text{not red)=}\frac{8}{10} \\ Pr(\text{not red)}=\frac{4}{5} \end{gathered}[/tex]Hence,
The final answer is = 4/5
