Question

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

• A. $12.8$
• B. $13$
• C. $13.5$
• D. $13.9$

Answer 1

The correct option is D $13.9$

Let the total population be $100k$
Percentage of people which read $A$ but not $B=25-8=17$%
Number of people which read $A$ but not $B=17k$
Percentage of people which read $B$ but not $A=20-8=12$%
Number of people which read $B$ but not $A=12k$

Number of people who look into advertisement$=30\%\text{of}17k+40\%\text{of}12k+50\%\text{of}8k$
$=5.1k+4.8k+4k=13.9k$
Therefore, percentage of the population who look into advertisement is $13.9\%$