Which of the following sets are finite or infinite.

The set of prime numbers less than $99$

Examine whether the following statements are true or false :

$\{ 1,2,3\}  \subset \{ 1,3,5\} $

State which of the following sets are finite or infinite :

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

Let $S=\{1,2,3, \ldots, 40)$ and let $A$ be a subset of $S$ such that no two elements in $A$ have their sum divisible by 5 . What is the maximum number of elements possible in $A$ ?

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

$\{ 3,4\}  \in A$

Let $A=\{1,2,3,4,5,6\} .$ Insert the appropriate symbol $\in$ or $\notin$ in the blank spaces:

$ 2 \, ....... \, A $