If C₁ = {x : x is a positive even composite number less than 15}, what is C₁?
Answer and explanation
Correct answer: C₁ = {4, 6, 8, 10, 12, 14}
The positive even numbers less than 15 are 2, 4, 6, 8, 10, 12, and 14. We must then apply the second condition: the number must be composite. Although 2 is even and positive, it is prime, not composite, so it must be removed. Every remaining listed number has factors other than 1 and itself. Hence C₁ = {4, 6, 8, 10, 12, 14}, so option A is correct.
Frequently asked questions
What is the correct answer to this question?
C₁ = {4, 6, 8, 10, 12, 14}
Why is this the correct answer?
The positive even numbers less than 15 are 2, 4, 6, 8, 10, 12, and 14. We must then apply the second condition: the number must be composite. Although 2 is even and positive, it is prime, not composite, so it must be removed. Every remaining listed number has factors other than 1 and itself. Hence C₁ = {4, 6, 8, 10, 12, 14}, so option A is correct.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Sets. Topic: Sets and their representations.
