Question

. If n(3) = 40, n(A) = 23, n(B') = 28 and n(AUB)' = 9, find n( AB) Answer:​

Answer 1

Answer:

n(A∪B)=n(A)+n(B)−n(A∩B)−−−−−−−(1)

Given n(A)=7

n(B)=9

n(A∪B)=14

Substituting in 1

14=7+9−n(A∩B)

⇒n(A∩B)=16−14=2