UPSC NDA Math Model Paper 4

Given: A = {1, 2, 3, 4}, B = {2, 4, 6, 8} and U = {1, 2, 3, 4, 5, 6, 7, 8, 9} where U is the universal set for A and B.
Here, we have to find the value of A' ∪ B'
As we know that, (A ∩ B)' = A' ∪ B'
⇒ A ∩ B = {1, 2, 3, 4} ∩ {2, 4, 6, 8} = {2, 4}
As we know that, A' = U - A
⇒ (A ∩ B)' = U - (A ∩ B) = {1, 2, 3, 4, 5, 6, 7, 8, 9} - {2, 4} = {1, 3, 5, 6, 7, 8, 9}