Question

Let n(A) 30, n(B) = 27 and n(A∪B) = 45, find: n(A ∩ B).

Answer 1

n(A) = 30, n(B) = 27 and n(A ∪ B) = 45

We know that,

n(A ∩ B) = n( A) + n(B) – n( A∪ B)

n(A ∩ B) = 30 + 27 – 45

n(A ∩ B) = 57 – 45 = 12