Which of the following are sets ? Justify your answer.
A collection of most dangerous animals of the world.
The collection of most dangerous animals of the world is not a well-defined collection because the criteria for determining the dangerousness of an animal can vary from person to person.
Hence, this collection is not a set.
Which of the following are sets ? Justify your answer.
A collection of novels written by the writer Munshi Prem Chand.
State whether each of the following set is finite or infinite :
The set of lines which are parallel to the $x\,-$ axis
Let $A, B$ and $C$ be three sets. If $A \in B$ and $B \subset C$, is it true that $A$ $\subset$ $C$ ?. If not, give an example.
Let $A=\{1,2,\{3,4\}, 5\} .$ Which of the following statements are incorrect and why ?
$\{\varnothing\} \subset A$
Let $S = \{ 0,\,1,\,5,\,4,\,7\} $. Then the total number of subsets of $S$ is