If A − B = ∅, which conclusion is always correct?
Answer and explanation
Correct answer: A ⊆ B
The difference A − B consists of elements that belong to A but do not belong to B; equivalently, A − B = A ∩ B'. If this set is empty, there is no element of A outside B. Therefore every element of A must be in B, which is exactly the statement A ⊆ B. The other conclusions do not necessarily follow.
Frequently asked questions
What is the correct answer to this question?
A ⊆ B
Why is this the correct answer?
The difference A − B consists of elements that belong to A but do not belong to B; equivalently, A − B = A ∩ B'. If this set is empty, there is no element of A outside B. Therefore every element of A must be in B, which is exactly the statement A ⊆ B. The other conclusions do not necessarily follow.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Sets. Topic: Complement of a Set and Its Properties.