Are the following pair of sets equal ? Give reasons.

$A = \{ x:x$ is a letter in the word ${\rm{FOLLOW }}\} $

$B = \{ y:y$ is a letter in the word $WOLF\} $

$A = \{ x:x$ is a letter in the word ${\rm{FOLLOW }}\} $

$B = \{ y:y$ is a letter in the word $WOLF\} $

The order in which the elements of a set are listed is not significant.

$\therefore A=B$

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

$1 \subset A$

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

$1 \in A$

State which of the following sets are finite or infinite :

$\{ x:x \in N$ and $2x - 1 = 0\} $

State which of the following sets are finite or infinite :

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

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

$\varnothing \subset A$