If U = R, A = (-infinity, 1), and B = (4, infinity), what is (A union B)'?
Answer and explanation
Correct answer: [1, 4]
A contains all real numbers less than 1, while B contains all real numbers greater than 4. Therefore, A union B excludes the endpoints 1 and 4 as well as every number between them. The complement in R consequently contains 1, 4, and all real numbers between them, so (A union B)' = [1, 4]. Thus option A is correct.
Frequently asked questions
What is the correct answer to this question?
[1, 4]
Why is this the correct answer?
A contains all real numbers less than 1, while B contains all real numbers greater than 4. Therefore, A union B excludes the endpoints 1 and 4 as well as every number between them. The complement in R consequently contains 1, 4, and all real numbers between them, so (A union B)' = [1, 4]. Thus option A is correct.
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.
