There are two boxes containing only orange and white pens.
Box $\mathbf{A}$ has 12 white pens and 4 orange pens.
Box $\mathbf{B}$ has 7 white pens and 13 orange pens.
A pen is randomly chosen from each box.
List these events from least likely to most likely.
Event 1: choosing a white or orange pen from Box A.
Event 2: choosing a white pen from Box A.
Event 3: choosing an orange pen from Box $B$.
Event 4: choosing a white pen from Box $B$.

Answer

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Answer

$\boxed{\text{Event 4, Event 3, Event 2, Event 1}}$

Steps

Step 1 ：Calculate the probability of each event:

Step 2 ：Event 1: choosing a white or orange pen from Box A. Probability: $\frac{16}{16} = 1$

Step 3 ：Event 2: choosing a white pen from Box A. Probability: $\frac{12}{16} = 0.75$

Step 4 ：Event 3: choosing an orange pen from Box B. Probability: $\frac{13}{20} = 0.65$

Step 5 ：Event 4: choosing a white pen from Box B. Probability: $\frac{7}{20} = 0.35$

Step 6 ：Sort the events from least likely to most likely:

Step 7 ：$\boxed{\text{Event 4, Event 3, Event 2, Event 1}}$