There are two boxes containing only black and orange pens. Box A has 4 black pens and 16 orange pens.
Box B has 2 black pens and 3 orange pens.

A pen is randomly chosen from each box. List these events from least likely to most likely.

Event 1: choosing a black pen from Box A.
Event 2: choosing a black or orange pen from Box A.
Event 3: choosing a white pen from Box B.
Event 4: choosing a black pen from Box B.

Event 3 -> Event 1 -> Event 4 -> Event 2

Step-by-step explanation:

The probability of choosing a certain pen is the number of that pen in the box over the total number of pens in the box.

So we have that:

Event 1: We have 4 black pen and 20 total pens, so P = 4 / 20 = 1 / 5

Event 2: All pens are black or orange so the probability is 1.

Event 3: We don't have white pens, so the probability is 0.

Event 4: We have 2 black pen and 5 total pens, so P = 2 / 5

Listing from least likely to most likely, we have:

Event 3 -> Event 1 -> Event 4 -> Event 2