NIMCET 2020 Question Paper with solutions

Concept:
- The cardinality of a set $\mathit{A}$ is the measure of the "number of elements" of the set. It is denoted by $\mathit{n}\left(\mathit{A}\right)$.
For example, a set containing 3 elements has a cardinality of 3 .
- If $\mathit{A}\subset \mathit{B}$, then $\mathit{A}\cup \mathit{B}=\mathit{B}$.
Calculations:
Since, $\mathit{A}\subset \mathit{B}$ and $\mathit{B}\subset \mathit{C}$, therefore $\mathit{A}\cup \mathit{B}\cup \mathit{C}=\mathit{C}$.
$\Rightarrow \mathit{n}\left(\mathit{A}\cup \mathit{B}\cup \mathit{C}\right)=\mathit{n}\left(\mathit{C}\right)$.
$\therefore$ The cardinality (number of elements) of $\mathit{A}\cup \mathit{B}\cup \mathit{C}=$ cardinality (number of elements) of $\mathit{C}$.