CA Foundation · Quantitative Aptitude · Sets, Relations and Functions, Limits and Continuity
For sets A and B, which of the following equals A ∩ (A ∪ B)?
The expression equals A. Every element of A is also in A ∪ B, so the intersection of A with A ∪ B keeps exactly the elements of A. This is the absorption law of sets.
- AB
- BA ∩ B
- CA ∪ B
- DACorrect
Explanation
Since A is contained in A ∪ B, their common part is all of A. This is the absorption law. A ∩ B would be correct only if A were a subset of B.
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