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

$B \cap D$

Consider the sets $A$ and $B$ of $A=\{2,4,6,8\}$ and $B=\{6,8,10,12\}$ Find $A \cap B .$

If $A=\{1,2,3,4\}, B=\{3,4,5,6\}, C=\{5,6,7,8\}$ and $D=\{7,8,9,10\} ;$ find

$B \cup C \cup D$

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

$B \cup D$

Let $A=\{a, b\}, B=\{a, b, c\} .$ Is $A \subset B \,?$ What is $A \cup B \,?$