Let A and B be two finite sets such that n(A) = 20, n(B) = 28 and n(A ∪ B) - Maths - Slant and Spread

Question

Let A and B be two finite sets such that n(A) = 20, n(B) = 28 and
n(A ∪ B) = 36, find n(A ∩ B)

Adarsh Saini · Accepted Answer

Using the formula n(A ∪ B) = n(A) + n(B) - n(A ∩ B)

then n(A ∩ B) = n(A) + n(B) - n(A ∪ B)

= 20 + 28 - 36

= 48 - 36

= 12

Let A and B be two finite sets such that n(A) = 20, n(B) = 28 and n(A ∪ B) = 36, find n(A ∩ B).