Question

Let A and B be two sets such that n(A) = 75, M(B) = 65 and n(A ∩ B) = 45, find: n(B – A)

Answer 1

n(A) = 75, n(B) = 65 and n(A ∩ B) = 45

We know that,

n(B – A) = n(B) – n(A ∩ B) n(B – A)

= 65 – 45 = 20