If A, B and C are any three non-empty sets such that any two of them are disjoint,
Question:

If AB and C are any three non-empty sets such that any two of them are disjoint, then (A ∪ ∪ C) (A ∩ ∩ C) = ____________.

Solution:

If A, B and are three non-empty sets such that any two of there are disjoint say

A ∩ B = ϕ

∩ C = ϕ and A ∩ C = ϕ

Then  A ∩ B ∩  ϕ

⇒ (A ⋃ ⋃ C) (A ∩ ∩ C) = (⋃ ⋃ C) ∩ ϕ

= ϕ