SOLUTION; Concept
Step1: Identify the giving information in the question
BOX A contains
[tex]\begin{gathered} 9\text{ yellow pens} \\ 6\text{ Black pens } \end{gathered}[/tex]
BOX B contains
[tex]\begin{gathered} 9\text{ yellow pens } \\ 11\text{ black pens} \end{gathered}[/tex]
Step2: Find the probability of each event
Event 1: Choosing a green pen from the Box B
[tex]\begin{gathered} \text{ Since there is no gr}een\text{ pen in the box, then probability of choosing a gr}en\text{ box in Box B is 0} \\ \text{then probability of choosing a gr}en\text{ box in Box B is 0} \\ Pr(E1)=0 \end{gathered}[/tex]
Event 2: Choosing a black pen from the Box B
[tex]P(E2)=\frac{11}{9+11}=\frac{11}{20}=0.55[/tex]
Event 3: Choosing a yellow or black pen from the Box A
Since Box A contains only a yellow or black pen then the probability is
[tex]Pr(E3)=1[/tex]
Event 4: Choosing a yellow pen from box A
Since there are 9 yellow pens in box A, the probability of choosing the yellow pen is
[tex]Pr(E4)=\frac{9}{9+6}=\frac{9}{15}=0.6[/tex]
Probability describes the likelihood of the event.
Hence From least likely to most likely the occurrence of the event is arranged as follows according to the probability of each event
[tex]\text{Event }1\rightarrow\text{ Event 2}\rightarrow\text{ Event 4}\rightarrow\text{ Event 3}[/tex]
