Question

Two newpapers $A$ 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 and $40$% of those who read $B$ but not $A$ also look into advertisements while $50$% of those who read $A$ and $B$ look into advertisements. Then the percentage of the population who look into advertisement is:

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

Answer 1

Answer: (C)

$13.9$

Let population $=100$
$n\left(A\right)=25;n\left(B\right)=20;n(A\cap B)=8;n(A\cap \overline{B})=17;n(\overline{A}\cap B)=12$
$\frac{30}{100}\times 17+\frac{40}{100}\times 12+\frac{50}{100}\times 8$
$5.1+4.8+4=13.9$