Let $A = \{\phi, \{\phi\}, 1, \{1, \phi\}, 7\}$. Which of the following is false?

Of the members of three athletic teams in a school,$21$ are in the cricket team,$26$ are in the hockey team,and $29$ are in the football team. Among them,$14$ play hockey and cricket,$15$ play hockey and football,and $12$ play football and cricket. Eight play all the three games. The total number of members in the three athletic teams is:

Write down the power set of $A = \{8, 9\}$.

Given the sets $A = \{1, 2, 3\}$,$B = \{3, 4\}$,and $C = \{4, 5, 6\}$,then $A \cup (B \cap C)$ is:

The range of $f(x) = \cos 2x - \sin 2x$ contains the set

Two newspapers $A$ and $B$ are published in a city. It is known that $25\%$ of the city population reads $A$ and $20\%$ reads $B$, while $8\%$ reads both $A$ and $B$. Further, $30\%$ of those who read $A$ but not $B$ look into advertisements, $40\%$ of those who read $B$ but not $A$ look into advertisements, and $50\%$ of those who read both $A$ and $B$ look into advertisements. Then the percentage of the population who look into advertisements is: