Question

7. You have two boxes of colored pens. The first box contains a red pen, a blue pen, and green pen. The second box contains a yellow pen, a red pen, and a black pen. Which set represents all the colors of the pens? (1 point)

Answer 1

If A={A,B,C} and B{A,D} the union between these two sets is given by AUB = [A,B,C,D} since you do NOT repeat the elements.
Apply the same logic to your pens and you'll have it done ;)