If A, B and C are three sets such that

• Sets

If A, B and C are three sets such that A ∩ B = A ∩ C and A ∪ B = A ∪ C, then

1. B = C
2. A = C
3. A ∩ B = φ
4. A = B

Solution

A ∪ B = A ∪ C

⇒ n (A ∪ B) = n(A ∪ C)

⇒ n(A) + n(B) – n(A ∩ B)

= n(A) + n(C) – n(A ∩C)

The correct option is A.