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

$ 8\, .......\, A $

Which of the following is a true statement

Which of the following are examples of the null set

Set of even prime numbers

In the following state whether $\mathrm{A = B}$ or not :

$A = \{ 2,4,6,8,10\} ;B = \{ x:x$ is positiveeven integer and $x\, \le \,10\} $

State which of the following sets are finite or infinite :

$\{ x:x \in N$ and ${x^2} = 4\} $