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

= 42–26

= 16.

Question

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

Philoid · Accepted Answer

n (A – B) = n (A ∪ B)– n (B)

= 42–26

= 16.