Set A and B have 3 and 6 elements respectively. What can be the minimum number of elements in A∪B
3
6
9
18
n(A∪B)=n(A)+n(B)-n(A∩B)=3+6-n(A∩B)
Since, maximum number of elements in A∩B=3
∴Minimum number of elements in A∪B=9-3=6.