Which is the roster form of W = {x ∈ ℕ : x is a factor of 18 and x is even}?
Answer and explanation
Correct answer: {2, 6, 18}
The positive factors of 18 are 1, 2, 3, 6, 9, and 18. We then apply the second condition, namely that the factor must be even. Among these factors, 2, 6, and 18 are even, while 1, 3, and 9 are odd. Therefore the roster form is W = {2, 6, 18}; numbers such as 4 and 8 are excluded because they are not factors of 18.
Frequently asked questions
What is the correct answer to this question?
{2, 6, 18}
Why is this the correct answer?
The positive factors of 18 are 1, 2, 3, 6, 9, and 18. We then apply the second condition, namely that the factor must be even. Among these factors, 2, 6, and 18 are even, while 1, 3, and 9 are odd. Therefore the roster form is W = {2, 6, 18}; numbers such as 4 and 8 are excluded because they are not factors of 18.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Sets. Topic: Sets and their representations.
