If $A \subseteq B$,then $A \cap B$ is equal to

Examine whether the following statement is true or false:
${1, 2, 3} \subset {1, 3, 5}$

If $n(A) = 3$ and $n(B) = 6$ and $A \subseteq B$,then the number of elements in $A \cap B$ is:

If $R$ is the set of real numbers and $Q$ is the set of rational numbers,then what is $R - Q$?

Show that the following four conditions are equivalent:
$(i) A \subset B, \quad (ii) A - B = \phi, \quad (iii) A \cup B = B, \quad (iv) A \cap B = A$

In the following,state whether $A = B$ or not:
$A = \{2, 4, 6, 8, 10\}$; $B = \{x : x \text{ is a positive even integer and } x \le 10\}$