If A = {1, 2, a} and B = {2, 1, 3} are equal sets, what is the value of a?
Answer and explanation
Correct answer: 3
Set order does not matter, so B contains the elements 1, 2, and 3. For A to equal B, it must contain exactly these same elements. Since 1 and 2 are already present in A, the remaining element represented by a must be 3. Values 1 or 2 would create repetition rather than supply the missing element, and 0 would make the sets unequal.
Frequently asked questions
What is the correct answer to this question?
3
Why is this the correct answer?
Set order does not matter, so B contains the elements 1, 2, and 3. For A to equal B, it must contain exactly these same elements. Since 1 and 2 are already present in A, the remaining element represented by a must be 3. Values 1 or 2 would create repetition rather than supply the missing element, and 0 would make the sets unequal.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Sets. Topic: The Empty Set, Finite and Infinite Sets, Equal Sets.
