Answer:
3 customers brought all the three papers.
Step-by-step explanation:
Let, D, O and N represents the three newspapers.
D = The daily times
O = The observer
N = The new Nigeria.
According to the given information,
[tex]n(D\cup O\cup N)=135, n(D)=70,n(O)=60,n(N)=50[/tex]
[tex]n(D\cap O)=17, n(O\cap N)=15, n(D\cap N)=16[/tex]
We know that,
[tex]n(A\cup B\cup C) = n(A) + n(B) + n(C)-n(A\cap B)-n(B\cap C)-n(C\cap A) + n(A\cap B\cap C)[/tex]
Using this formula, we get
[tex]n(D\cup O\cup N) = n(D)+n(O) + n(N)-n(D\cap O)-n(O\cap N)-n(N\cap D) + n(D\cap O\cap N)[/tex]
[tex]135 =70+60+50-17-15-16 +n(D\cap O\cap N)[/tex]
[tex]135 =132+n(D\cap O\cap N)[/tex]
[tex]135 -132=n(D\cap O\cap N)[/tex]
[tex]3=n(D\cap O\cap N)[/tex]
Therefore, 3 customers brought all the three papers.
