Question

A survey was conducted of 100 people to find out whether they had read recent issues of Golmal, a monthly magazine. The summarized information regarding readership in 3 months is given below:
Only September: 18;
September but not August: 23;
July: 48;
July and August: 10;
September and July: 8;
September: 28;
None of the three months: 24.
What is the number of surveyed people who have read exactly two consecutive issues (out of the three)?

• A. 7
• B. 9
• C. 12
• D. 14

Answer 1

The correct option is B 9

Putting the given information in the form of a Venn diagram, we get

$n(J\cup A\cup S)=100-24=76n(S\cap J)=8;n\left(onlyS\right)=18$
n(S but not A) = 23 = $\stackrel{18}{\stackrel{}{n\left(onlyS\right)}}+\underset{5}{\underset{}{n\left(S\right)-n(S\cap A)}}$
$n(S\cap A\cap J)=n(S\cap J)-5=8-5=3)$
To find the people who have read exactly 2 consecutive issues (out of 3) we shall find the people reading J & A and A & S.
Hence required no. = 7 + 2 = 9