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 $S$ and $T$ are two sets such that $S$ has $21$ elements, $T$ has $32$ elements, and $S$ $\cap \,T$ has $11$ elements, how many elements does $S\, \cup$ $T$ have?
If $A = \{ x:x$ is a natural number $\} ,B = \{ x:x$ is an even natural number $\} $ $C = \{ x:x$ is an odd natural number $\} $ and $D = \{ x:x$ is a prime number $\} ,$ find $A \cap D$
State whether each of the following statement is true or false. Justify you answer.
$\{2,6,10\}$ and $\{3,7,11\}$ are disjoint sets.
Using that for any sets $\mathrm{A}$ and $\mathrm{B},$
$A \cup(A \cap B)=A$