Which option is the roster form of U₁ = {x : x ∈ ℕ, 10 ≤ x ≤ 40, and x has the digit 3}?
Answer and explanation
Correct answer: U₁ = {13, 23, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39}
The roster form lists every natural number from 10 through 40 that contains the digit 3 in at least one position. The numbers 13 and 23 contain 3 in the units place, while 30 through 39 contain it in the tens place. Number 40 does not contain 3, and 43 is outside the interval. Therefore option A is complete and correct.
Frequently asked questions
What is the correct answer to this question?
U₁ = {13, 23, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39}
Why is this the correct answer?
The roster form lists every natural number from 10 through 40 that contains the digit 3 in at least one position. The numbers 13 and 23 contain 3 in the units place, while 30 through 39 contain it in the tens place. Number 40 does not contain 3, and 43 is outside the interval. Therefore option A is complete and correct.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Sets. Topic: Sets and their representations.
