Question

If $A=\{x:x\text{is a prime number}\}$ and $B=\{x:x\text{is a composite number}\}$, then $A$ and $B$ are ___ sets.

• A. disjoint
• B. overlapping
• C. equal
• D. finite

Answer 1

The correct option is A disjoint

Two sets are said to be disjoint if they have no element in common.
A number cannot be both prime and composite, and thus, $A$ and $B$ are disjoint. (not overlapping, not equal).
Also, the sets are infinite.