If $A$ and $B$ are two sets,then $(A \cap B)'$ is equal to

$A$ and $B$ are events such that $P(A)=0.42$,$P(B)=0.48$ and $P(A \cap B)=0.16$. Determine $P(\text{not } B)$.

Consider the experiment of rolling a die. Let $A$ be the event 'getting a prime number' and $B$ be the event 'getting an odd number'. Write the set representing the event 'not $A$'.

Taking the set of natural numbers as the universal set,write down the complement of the following set:
$A = \{ x : x \text{ is a perfect square} \}$

Let $U$ be the universal set of all the students of Class $XI$ of a coeducational school and $A$ be the set of all girls in Class $XI$. Find $A'$.

Taking the set of natural numbers as the universal set,write down the complement of the following set:
$A = \{x: 2x + 5 = 9\}$