When is the set statement: (A⊕B) = (A ∪ B) true? "When is the set statement:

(A⊕B) = (A ∪ B)

a true statement? Is it true sometimes, never, or always? If it is sometimes, state the cases where it is."
How would you go about finding the answer to the question or ones like this one? 
Thanks for your time!

If I've made the right assumptions in my comment above, a good way to approach this problem is by drawing a Venn diagram.
Here's $A\oplus B$:

Here's $A\cup B$:

So, the area that's filled in in $A\cup B$ but not $A\oplus B$ is $A\cap B$. What do I need to be true about $A\cap B$ to make the two Venn diagrams have the same area filled in?
