If ${N_a} = \{ an:n \in N\} ,$ then ${N_3} \cap {N_4} = $
If $n(A) = 3$ and $n(B) = 6$ and $A \subseteq B$. Then the number of elements in $A \cap B$ is equal to
Find the union of each of the following pairs of sets :
$X =\{1,3,5\} \quad Y =\{1,2,3\}$
If the sets $A$ and $B$ are defined as $A = \{ (x,\,y):y = {1 \over x},\,0 \ne x \in R\} $ $B = \{ (x,y):y = - x,x \in R\} $, then
Let $A$ and $B$ be two sets. Then