If $A = \{ 2,\,4,\,5\} ,\,\,B = \{ 7,\,\,8,\,9\} ,$ then $n(A \times B)$ is equal to
$6$
$9$
$3$
$0$
If $R$ is the set of all real numbers, what do the cartesian products $R \times R$ and $R \times R \times R$ represent?
Let $A=\{1,2,3\}, B=\{3,4\}$ and $C=\{4,5,6\} .$ Find
$A \times(B \cup C)$
If $(x+1, y-2)=(3,1),$ find the values of $\mathrm{x}$ and $\mathrm{y}$.
If $n(A) = 4$, $n(B) = 3$, $n(A \times B \times C) = 24$, then $n(C) = $
If $P,Q$ and $R$ are subsets of a set $A$, then $R × (P^c \cup Q^c)^c =$