Question

There are 100 families in a society, 40 families buy newspaper A, 30 families buy newspaper B, 30
families buy newspaper C, 10 families buy newspaper A and B, 8 families buy newspaper B and C, 5
families buy newspaper A and C, 3 families buy newspaper A, B and C, then the number of families
who do not buy any of the newspaper A,B,C ​

Answer 1

n(A ∪ B ∪ C) = n(A) + n(B) + n(C) - n(AB) - n(BC) - n(CA) + n(ABC) = 80 (number of families reading atleast one newspapers A, B and C) ∴ Total number of families = 100 So, 20 families do not read any newspaper.

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