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. 13.5
• C. 13.9
• D. 13

Answer 1

Answer: (C)

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