Question

State whether the following sets into empty, finite and infinite sets. In case of (non-empty) finite sets, mention the cardinal number.
$\{x:x\in N$ and $x$ is a composite number $<12\}$

Answer 1

Let, $A=\{x:xeN$ and $x$ is a composite number $<12\}$

$\Rightarrow A=\{4,6,8,9,10\}$

Hence, the given set is finite cardinal number is $=5$