Let A and B be two sets in the same universal set.
Question:

Let $A$ and $B$ be two sets in the same universal set. Then, $A-B=$

(a) $A \cap B$

(b) $A^{\prime} \cap B$

(c) $A \cap B^{\prime}$

(d) none of these.

Solution:

(c) $A \cap B^{\prime}$

$A-B$ belongs to those elements of $A$ that do not belong to $B$.

$\therefore A-B=A \cap B^{\prime}$