Which of the following sets is not equal to {1, 2, 3}?
Answer and explanation
Correct answer: {1, 2, 3, 4}
Two sets are equal when they contain exactly the same elements; the order of listing does not matter, and repeated elements are written only once. Options A and D contain 1, 2, and 3 in a different order. Option B also represents {1, 2, 3}, because repetition does not create a new element. Option C contains the additional element 4, so it is not equal.
Frequently asked questions
What is the correct answer to this question?
{1, 2, 3, 4}
Why is this the correct answer?
Two sets are equal when they contain exactly the same elements; the order of listing does not matter, and repeated elements are written only once. Options A and D contain 1, 2, and 3 in a different order. Option B also represents {1, 2, 3}, because repetition does not create a new element. Option C contains the additional element 4, so it is not equal.
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.
