Question

If $A=\{x:x\text{is an even number and}0<x<10\}$ and $B=\{2,3,5,7\}$, then the number of elements in $A\cup B$ is

Answer 1

Given
$A=\{2,4,6,8\}$
$B=\{2,3,5,7\}$
then
$A\cup B=\{2,3,4,5,6,7,8\}$
Hence, the number of element $=7$