If A = {x ∈ ℕ : x is a factor of 18}, what type of set is A?
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Answer and explanation
Correct answer: A finite set
The positive natural-number factors of 18 are 1, 2, 3, 6, 9, and 18. Thus A = {1, 2, 3, 6, 9, 18}. This list is complete because every factor of 18 occurs in one of the factor pairs 1×18, 2×9, or 3×6. Since A has six countable elements, it is a finite set.
Frequently asked questions
What is the correct answer to this question?
A finite set
Why is this the correct answer?
The positive natural-number factors of 18 are 1, 2, 3, 6, 9, and 18. Thus A = {1, 2, 3, 6, 9, 18}. This list is complete because every factor of 18 occurs in one of the factor pairs 1×18, 2×9, or 3×6. Since A has six countable elements, it is a finite set.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Sets. Topic: The Empty Set, Finite and Infinite Sets, Equal Sets.
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