Let U = {x : x ∈ N, 1 ≤ x ≤ 14} and A = {x : x ∈ U, x is odd}. What is n(A′)?
Answer and explanation
Correct answer: 7
The universal set contains the natural numbers from 1 through 14. Set A consists of the odd numbers 1, 3, 5, 7, 9, 11, and 13. Its complement within U therefore consists of the even numbers 2, 4, 6, 8, 10, 12, and 14. There are seven such numbers, so n(A′) = 7. The answer depends on the stated universal set; numbers outside U are not considered.
Frequently asked questions
What is the correct answer to this question?
7
Why is this the correct answer?
The universal set contains the natural numbers from 1 through 14. Set A consists of the odd numbers 1, 3, 5, 7, 9, 11, and 13. Its complement within U therefore consists of the even numbers 2, 4, 6, 8, 10, 12, and 14. There are seven such numbers, so n(A′) = 7. The answer depends on the stated universal set; numbers outside U are not considered.
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.
