State which of the following sets are finite or infinite :

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

Which of the following sets are finite or infinite.

$\{1,2,3, \ldots 99,100\}$

If $Q = \left\{ {x:x = {1 \over y},\,{\rm{where \,\,}}y \in N} \right\}$, then

Find the pairs of equal sets, if any, give reasons:

$A = \{ 0\} ,$

$B = \{ x:x\, > \,15$ and $x\, < \,5\} $

$C = \{ x:x - 5 = 0\} ,$

$D = \left\{ {x:{x^2} = 25} \right\}$

$E = \{ \,x:x$ is an integral positive root of the equation ${x^2} - 2x - 15 = 0\,\} $

Write the following as intervals :

$\{ x:x \in R,3\, \le \,x\, \le \,4\} $