If S = {x ∈ ℕ : x is a multiple of 7 and x < 30}, which is the correct roster form of S?
Answer and explanation
Correct answer: {7, 14, 21, 28}
The positive natural-number multiples of 7 are 7, 14, 21, 28, 35, and so on. The condition x < 30 retains only 7, 14, 21, and 28. The number 35 is excluded because it is greater than 30; 0 is not included under the natural-number convention used here, and 1 is not a multiple of 7. Thus S = {7, 14, 21, 28}.
Frequently asked questions
What is the correct answer to this question?
{7, 14, 21, 28}
Why is this the correct answer?
The positive natural-number multiples of 7 are 7, 14, 21, 28, 35, and so on. The condition x < 30 retains only 7, 14, 21, and 28. The number 35 is excluded because it is greater than 30; 0 is not included under the natural-number convention used here, and 1 is not a multiple of 7. Thus S = {7, 14, 21, 28}.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Sets. Topic: Sets and their representations.
