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; September and July: 8; September: 28; July: 48; July and August: 10; None of the three months: 24.
What is the number of surveyed people who have read exactly two consecutive issues (out of the three)?


(1) 7 (2) 9(3) 12
(4) 14 (5) 17

Solution:


100 – 24 = 76 had read at least one issue.
If x people read all the three issues, then (8 – x) people read only the September and July issues.
23 people read the September issue but not the August issue.
18 + 8 – x = 23
x = 3
As 28 people read the September issue, [28 – (8 – 3) – 3 – 18] = 2 people read only the August and September issues.
As 10 people read the July and August issues, 10 – 3 = 7 people read only the July and August issues.
The number of people who have read exactly two consecutive issues = 7 + 2 = 9
Hence, option 2.