If $X=\{a, b, c, d\}$ and $Y=\{f, b, d, g\},$ find
$X \cap Y$
Let $A = \{ (x,\,y):y = {e^x},\,x \in R\} $, $B = \{ (x,\,y):y = {e^{ - x}},\,x \in R\} .$ Then
If $A$ and $B$ are not disjoint sets, then $n(A \cup B)$ is equal to
If $n(A) = 3$, $n(B) = 6$ and $A \subseteq B$. Then the number of elements in $A \cup B$ is equal to
If $A=\{1,2,3,4\}, B=\{3,4,5,6\}, C=\{5,6,7,8\}$ and $D=\{7,8,9,10\} ;$ find
$A \cup B$