Which option is an example of a closed interval?
Answer and explanation
Correct answer: [4,9]
A closed interval contains both of its finite endpoints. Square brackets show inclusion, so [4,9] represents all real numbers x for which 4≤x≤9, including both 4 and 9. Option A excludes both endpoints and is open. Options C and D include one endpoint but exclude the other, so they are half-open intervals rather than closed intervals.
Frequently asked questions
What is the correct answer to this question?
[4,9]
Why is this the correct answer?
A closed interval contains both of its finite endpoints. Square brackets show inclusion, so [4,9] represents all real numbers x for which 4≤x≤9, including both 4 and 9. Option A excludes both endpoints and is open. Options C and D include one endpoint but exclude the other, so they are half-open intervals rather than closed intervals.
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.
