Which is the roster form of X = {x : x = 3n − 1, n ∈ N, 1 ≤ n ≤ 5}?
Answer and explanation
Correct answer: X = {2, 5, 8, 11, 14}
The governing concept is substituting every allowed natural-number value into a set-builder rule. Since 1 ≤ n ≤ 5, the possible values are 1, 2, 3, 4, and 5. Using x = 3n − 1 gives 2, 5, 8, 11, and 14 respectively. Therefore the roster form is X = {2, 5, 8, 11, 14}, so option A is correct. Option B reflects 3n − 2, while C lists 3n and D begins with an invalid n = 0.
Frequently asked questions
What is the correct answer to this question?
X = {2, 5, 8, 11, 14}
Why is this the correct answer?
The governing concept is substituting every allowed natural-number value into a set-builder rule. Since 1 ≤ n ≤ 5, the possible values are 1, 2, 3, 4, and 5. Using x = 3n − 1 gives 2, 5, 8, 11, and 14 respectively. Therefore the roster form is X = {2, 5, 8, 11, 14}, so option A is correct. Option B reflects 3n − 2, while C lists 3n and D begins with an invalid n = 0.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Sets. Topic: Sets and their representations.
