Which option is the roster form of Z={x: x is a positive factor of 18}?
Answer and explanation
Correct answer: Z={1,2,3,6,9,18}
The governing idea is conversion from set-builder form to roster form. A positive factor of 18 must divide 18 exactly. The factor pairs 1×18, 2×9, and 3×6 produce the complete list {1,2,3,6,9,18}; therefore option A is correct. Option B is mainly a list of even numbers, C contains multiples of 18, and D includes 5, which is not a factor of 18.
Frequently asked questions
What is the correct answer to this question?
Z={1,2,3,6,9,18}
Why is this the correct answer?
The governing idea is conversion from set-builder form to roster form. A positive factor of 18 must divide 18 exactly. The factor pairs 1×18, 2×9, and 3×6 produce the complete list {1,2,3,6,9,18}; therefore option A is correct. Option B is mainly a list of even numbers, C contains multiples of 18, and D includes 5, which is not a factor of 18.
Which subject and chapter does this question cover?
This is a Class 9 Mathematics question. Chapter: Number Systems. Topic: General chapter practice.
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