Question

$A\cup B=A\cap B$ if and only if

• A. A is an empty set
• B. B is an empty set
• C. Both A and B are empty sets
• D. Both A and B are non-empty sets

Answer 1

The correct option is C Both A and B are empty sets

Solution:- Lets assume A is an empty set and B=$\{a,b\}$

Now $A\cup B=\{a,b\}$ and $A\cap B=\oslash$, so in all cases other than C , the condition is not satisfied. So C is the correct answer.