If K = {x ∈ ℕ : x is a factor of 20}, which statement is correct?
Answer and explanation
Correct answer: K = {1, 2, 4, 5, 10, 20}
A factor of 20 is a natural number that divides 20 exactly, leaving no remainder. The factor pairs are 1 × 20, 2 × 10, and 4 × 5. Thus the complete list of positive natural factors is 1, 2, 4, 5, 10, and 20. Both 1 and 20 must be included, because 1 divides every natural number and every number divides itself. Hence option A is correct.
Frequently asked questions
What is the correct answer to this question?
K = {1, 2, 4, 5, 10, 20}
Why is this the correct answer?
A factor of 20 is a natural number that divides 20 exactly, leaving no remainder. The factor pairs are 1 × 20, 2 × 10, and 4 × 5. Thus the complete list of positive natural factors is 1, 2, 4, 5, 10, and 20. Both 1 and 20 must be included, because 1 divides every natural number and every number divides itself. Hence 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.
