If $A = \{3, 5, 7, 9, 11\}$,$B = \{7, 9, 11, 13\}$,$C = \{11, 13, 15\}$,and $D = \{15, 17\}$,find $A \cap B$.

Show that for any sets $A$ and $B$,$A = (A \cap B) \cup (A - B)$ and $A \cup (B - A) = (A \cup B).$

If $A$ and $B$ are any two events of a sample space,then the set-theoretic description for the event: "Exactly one of the events $A, B$ occurs" is
(Here $E^c$ denotes the complement of the event $E$)

Which of the following pairs of sets are disjoint?
${1, 2, 3, 4}$ and ${x : x \text{ is a natural number and } 4 \le x \le 6}$

If $A$ and $B$ are disjoint sets,then $n(A \cup B) = $

Find the union of each of the following pairs of sets:
$A = \{1, 2, 3\}, B = \varnothing$