Question

The diagram shows the universal set U = {parallelograms}.

Set A represents parallelograms with four congruent sides, while B represents parallelograms with four congruent angles.

Circles A and B overlap. Circle A contains 12, Circle B contains 6, and the overlap contains 8. Number 3 is outside of the circles.

How many of the parallelograms fall into the category A U B?

6
8
18
26

Answer 1

Add the three regions inside the circles: A-only 12 + B-only 6 + overlap 8 = 26.

So |A ∪ B| = 26.