You have two boxes of colored pens. The first box contains a red pen, a blue pen, and a green pen. The second box contains a yellow pen, a red pen, and a black pen. What is the set that represents all the pens

The set that represents all the pens would be: {red pen, blue pen, green pen, yellow pen, black pen}.

The set that represents all the pens in both boxes can be represented as follows:

{red pen, blue pen, green pen, yellow pen, black pen}

To find the set that represents all the pens, we can list all the individual pens and combine them into a single set.

First box:
- Red pen
- Blue pen
- Green pen

Second box:
- Yellow pen
- Red pen
- Black pen

Combining both boxes, we have:

- Red pen
- Blue pen
- Green pen
- Yellow pen
- Black pen

The set that represents all the pens is {Red pen, Blue pen, Green pen, Yellow pen, Black pen}.