Question

Let n(A) = 31, n(B) = 20 and n(A ∩ B) = 6, find: n (A - B).

Answer 1

n(A) = 31, n(B) = 20 and n(A ∩ B) = 6

We know that,

n(A – B) = n(A) – n(A ∩ B)

n(A - B) = 31 - 6 = 25