Let $A$ and $B$ be two sets,then $(A \cup B)' \cup (A' \cap B)$ is equal to

In a certain office,$72 \%$ of the workers prefer cold drink and $44 \%$ prefer tea. If each of them prefers cold drink or tea and $40$ like both,then the total number of workers in the office is

If $A = \{a, b\}$,$B = \{2, 3, 5, 6, 7\}$ and $C = \{5, 6, 7, 8, 9\}$,find $A \times (B \cap C)$.

Write down the power set of $C = \{1, \{2\}\}$.

If $A = \{x : x \text{ is a multiple of } 4\}$ and $B = \{x : x \text{ is a multiple of } 6\}$,then $A \cap B$ consists of all multiples of

In an examination,$40 \%$ students failed in Hindi,$50 \%$ students failed in English. If $21 \%$ students failed in both the subjects,find the percentage of those who passed in Hindi.