Which of the following are sets ? Justify your answer.

The collection of questions in this chapter.

Which of the following are sets ? Justify your answer.

The collection of ten most talented writers of India.

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.

Write the following as intervals :

$\{ x:x \in R,0\, \le \,x\, < \,7\} $

Let $A=\{1,2,\{3,4\}, 5\} .$ Which of the following statements are incorrect and why ?

$\varnothing \subset A$

State which of the following sets are finite or infinite :

$\{ x:x \in N$ and $x$ is prime $\} $