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

$A = \{ x:x$ is a multiple of $10\} ;B = \{ 10,15,20,25,30 \ldots  \ldots \} $

In the following state whether $A=B$ or not :

$A=\{4,8,12,16\} ; B=\{8,4,16,18\}$

Which of the following are examples of the null set

$\{ y:y$ is a point common to any two parallellines $\} $

Write the following intervals in set-builder form :

$\left( { - 3,0} \right)$

The smallest set $A$ such that $A  \cup  \{1, 2\} = \{1, 2, 3, 5, 9\}$ is

Let $A, B$ and $C$ be three sets. If $A \in B$ and $B \subset C$, is it true that $A$ $\subset$ $C$ ?. If not, give an example.