If A and B are subsets of a set X, then {A ∩ (X - B)} ∪ B is equal to
If A and B are subsets of a set X, then {A ∩ (X - B)} ∪ B is equal to Correct Answer A ∪ B
Concept:
- Associative Laws: For any three sets A, B and C, we have
- (A ∪ B) ∪ C = A ∪ (B ∪ C)
- A ∩ (B ∩ C) = (A ∩ B) ∩ C
- Distributive Laws: For any three sets A, B and C, we have
- A ∪ (B ∩ C) = (A ∪ B) ∩ (A ∪ C)
- A ∩ (B ∪ C) = (A ∩ B) ∪ (A ∩ C)
Calculation:
Given: A and B are subsets of a set X
As we know that, X - B = X ∩ B’
⇒ A ∩ (X - B) = A ∩ (X ∩ B’)
⇒ A ∩ (X ∩ B’) = (A ∩ X) ∩ B’ -------------(Associative Law)
⇒ A ∩ (X ∩ B’) = (A ∩ X) ∩ B’ = A ∩ B’ ---------------(A ⊆ X)
⇒ A ∩ (X - B) = A ∩ B’
⇒ {A ∩ (X - B)} ∪ B = (A ∩ B’) ∪ B = (A ∪ B) ∩ (B’ ∪ B) ------------(Distributive Law)
⇒ {A ∩ (X - B)} ∪ B = (A ∪ B) ∩ X -------------(∵ B’ ∪ B = X)
⇒ {A ∩ (X - B)} ∪ B = (A ∪ B) ∩ X = A ∪ B ------------(∵ A and B are subsets of a set X)
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Feb 20, 2025