Question

If the set $A$ has $3$ elements and the set $B=\{3,4,5\}$ then find the number of elements in $(A\times B)$?

Answer 1

It is given that set $A$ has $3$ elements and the elements of set $B$ are $3,4$ and $5$
$\Rightarrow$ Number of elements in set $B=3$
Number of elements in $(A\times B)$
$=$ (Number of elements in $A$) $\times$ (Number of elements in $B$)
$=3\times 3=9$
Thus the number of elements in $(A\times B)$ is $9$