Q5 of 162 Page 1

Let A and B be two sets such that : n (A) = 20, n (A ∪ B) = 42 and n (A ∩ B) = 4. Find

n (B)

We know,


n (A ∪ B) = n(A) + n(B) – n (A ∩ B)


Substituting the values we get


42 = 20+ n (B) – 4


42 = 16+ n (B)


n (B) =26


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