What is the correct roster form of I={x: x is a positive divisor of 12}?
Answer and explanation
Correct answer: I={1,2,3,4,6,12}
A positive divisor of 12 is a positive integer that divides 12 exactly, leaving remainder zero. Check the factor pairs 1×12, 2×6, and 3×4. These produce the complete positive divisor list 1, 2, 3, 4, 6, and 12. Option B omits 1 and 12, option C omits 4 and 6, and option D incorrectly includes 9, since 12÷9 is not an integer. Therefore option A is correct.
Frequently asked questions
What is the correct answer to this question?
I={1,2,3,4,6,12}
Why is this the correct answer?
A positive divisor of 12 is a positive integer that divides 12 exactly, leaving remainder zero. Check the factor pairs 1×12, 2×6, and 3×4. These produce the complete positive divisor list 1, 2, 3, 4, 6, and 12. Option B omits 1 and 12, option C omits 4 and 6, and option D incorrectly includes 9, since 12÷9 is not an integer. Therefore option A is correct.
Which subject and chapter does this question cover?
This is a Class 9 Mathematics question. Chapter: Common Questions.
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