The shaded region in the given figure is

If $A=\{3,6,9,12,15,18,21\}, B=\{4,8,12,16,20\},$ $C=\{2,4,6,8,10,12,14,16\}, D=\{5,10,15,20\} ;$ find

$B-D$

If $A, B$ and $C$ are three sets such that  $A \cap B = A \cap C$ and $A \cup B = A \cup C$ then

Consider the sets $X$ and $Y$ of $X = \{ $ Ram , Geeta, Akbar $\} $ and $Y = \{ $ Geeta, David, Ashok $\} $ Find $X \cap Y$

Let $A, B$ and $C$ be sets such that $\phi  \ne A \cap B \subseteq C$. Then which of the following statements is not true ?

Let $A$ and $B$ be two sets in the universal set. Then $A - B$ equals