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

$A \cap \left( {B \cup D} \right)$

If ${N_a} = [an:n \in N\} ,$ then ${N_5} \cap {N_7} = $

Let $A=\{1,2,3,4,5,6,7,8,9,10\}$ and $B=\{2,3,5,7\} .$ Find $A \cap B$ and hence show that $A \cap B = B$

Let $A :\{1,2,3,4,5,6,7\}$. Define $B =\{ T \subseteq A$ : either $1 \notin T$ or $2 \in T \}$ and $C = \{ T \subseteq A : T$ the sum of all the elements of $T$ is a prime number $\}$. Then the number of elements in the set $B \cup C$ is $\dots\dots$

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

$B \cap D$

If $A$ and $B$ are any two sets, then $A \cup (A \cap B) $ is equal to