If A = {x ∈ Z : x is divisible by 10 and 0 < x < 100}, which is A?
Answer and explanation
Correct answer: A = {10, 20, 30, 40, 50, 60, 70, 80, 90}
The integer multiples of 10 are ..., −20, −10, 0, 10, 20, ..., 100, .... The strict inequalities 0 < x < 100 exclude 0 and 100, as well as all negative values. The remaining multiples are 10, 20, 30, 40, 50, 60, 70, 80, and 90, so option A gives the complete roster form.
Frequently asked questions
What is the correct answer to this question?
A = {10, 20, 30, 40, 50, 60, 70, 80, 90}
Why is this the correct answer?
The integer multiples of 10 are ..., −20, −10, 0, 10, 20, ..., 100, .... The strict inequalities 0 < x < 100 exclude 0 and 100, as well as all negative values. The remaining multiples are 10, 20, 30, 40, 50, 60, 70, 80, and 90, so option A gives the complete roster form.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Sets. Topic: The Empty Set, Finite and Infinite Sets, Equal Sets.
