InterviewSolution
Saved Bookmarks
InterviewSolution
| 1. |
In a certain city only two newspapers A and B are published, it is known that `25%` of thecity population reads A and `20%` reads B, while `8%` reads both A and B. It is also knownthat 30% of those who read A but not B look int advertisements and 40% of thosewho read B bu not A look into advertisements while 50% of those who read both A and Blook into advertisements What is the percentage of the population reads an advertisement?[1984] |
|
Answer» Correct Answer - A::C Let P(A) and P(B) denote respectively the percentage of city population that reads newspapers A and B. Then, `P(A)=(25)/(100)=(1)/(4),P(B)=(20)/(100)=(1)/(5)`, `P(AnnB)=(8)/(100)=(2)/(25)`, P(AnnB)=P(A)-P(AnnB)=(1)/(4)-(2)/(25)=(17)/(100)`, `P(barAnnB)=P(B)-P(AnnB)=(1)/(5)-(2)/(25)=(3)/(25)` Let P(C ) be the probability that the population who reads advertisements. `:. P(C )=30%` of `P(AnnbarB)+40%` of `P(barAnnB)+50%` of `P(AnnB)` [since, `AnnbarB,barAnnB` and `AnnB` are all mutually exclusive] `rArr P(C )=(3)/(10)xx(17)/(100)+(2)/(5)xx(3)/(25)+(1)/(2)xx(2)/(25)=(139)/(1000)=13.9%` |
|