Let $A=\{1,2,\{3,4\}, 5\} .$ Which of the following statements are incorrect and why ?
$\{\varnothing\} \subset A$
Which of the following sets are finite or infinite.
The set of positive integers greater than $100$
Write the following intervals in set-builder form :
$\left( {6,12} \right]$
From the sets given below, select equal sets:
$A=\{2,4,8,12\}, B=\{1,2,3,4\}, C=\{4,8,12,14\}, D=\{3,1,4,2\}$
$E=\{-1,1\}, F=\{0, a\}, G=\{1,-1\}, H=\{0,1\}$
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 $A$ ?