If A = {m,n,p,q} and B = {n,q,r,s}, what is A ∪ (B \ A)?
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Answer and explanation
Correct answer: {m,n,p,q,r,s}
The difference B \ A contains the elements in B that are absent from A. Since n and q are common, B \ A = {r,s}. Taking the union with A adds r and s to all elements already in A: {m,n,p,q} ∪ {r,s} = {m,n,p,q,r,s}. Thus option A is correct; option B stops before the final union.
Frequently asked questions
What is the correct answer to this question?
{m,n,p,q,r,s}
Why is this the correct answer?
The difference B \ A contains the elements in B that are absent from A. Since n and q are common, B \ A = {r,s}. Taking the union with A adds r and s to all elements already in A: {m,n,p,q} ∪ {r,s} = {m,n,p,q,r,s}. Thus option A is correct; option B stops before the final union.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Sets. Topic: Operations on Sets (Union, Intersection, Difference).
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