If A = {1, 2, 3} and B = {1, 2, 3, 4}, what is true about A ⊂ B?
Answer and explanation
Correct answer: It is true, and A is a proper subset of B.
Every element of A, namely 1, 2, and 3, is also an element of B. In addition, B contains the element 4, which is not in A. Thus A is contained in B but is not equal to B; this is exactly the definition of a proper subset, written A ⊂ B. Option B contradicts the extra element 4. Options C and D misunderstand the definition: the absence of 4 from A supports the proper-subset relation rather than disproving it.
Frequently asked questions
What is the correct answer to this question?
It is true, and A is a proper subset of B.
Why is this the correct answer?
Every element of A, namely 1, 2, and 3, is also an element of B. In addition, B contains the element 4, which is not in A. Thus A is contained in B but is not equal to B; this is exactly the definition of a proper subset, written A ⊂ B. Option B contradicts the extra element 4. Options C and D misunderstand the definition: the absence of 4 from A supports the proper-subset relation rather than disproving it.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Sets. Topic: Equal sets and Subsets.
