Question

Two sets A and B are non empty sets , if 2[n(AUB)]= 3[n(A)]=4[n(B)] and n(AnB) = 12 then. find n(AUB)​

Answer 1

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