Which is the correct set-builder form of {4,8,12,16,20}?
Answer and explanation
Correct answer: {x:x=4n, n∈N, 1≤n≤5}
The governing idea is set-builder notation: describe every member using a rule and a permitted parameter range. Here x must be a multiple of 4, and n takes the values 1, 2, 3, 4, and 5. Thus x=4n produces exactly 4, 8, 12, 16, and 20, with no extra elements. Option B produces even numbers, C produces squares, and D produces numbers one more than a multiple of 4. Therefore A is correct.
Frequently asked questions
What is the correct answer to this question?
{x:x=4n, n∈N, 1≤n≤5}
Why is this the correct answer?
The governing idea is set-builder notation: describe every member using a rule and a permitted parameter range. Here x must be a multiple of 4, and n takes the values 1, 2, 3, 4, and 5. Thus x=4n produces exactly 4, 8, 12, 16, and 20, with no extra elements. Option B produces even numbers, C produces squares, and D produces numbers one more than a multiple of 4. Therefore A is correct.
Which subject and chapter does this question cover?
This is a Class 9 Mathematics question. Chapter: Number Systems.
Student feedback
Was this question useful?
👍 0 Helpful 👎 0 Not helpful
Yes 0% No 0%
0 responsesStudent Reviews
No published reviews yet.
