Sets Relations And Functions Question 65

Question: Sets A and B have 3 and 6 elements respectively. What can be the minimum number of elements in A U B

[MNR 1987; Karnataka CET 1996]

Options:

A) 3

B) 6

C) 9

D) 18

Show Answer

Answer:

Correct Answer: B

Solution:

  • n(A È B) = n + n - n(A Ç B) = $ 3+6-n(A\cap B) $ Since, maximum number of elements in $ A\cap B=3 $
    $ \therefore $ Minimum number of elements in $ A\cup B=9-3=6 $ .