What is the roster form of B = {x : x is an odd natural number and x < 10}?
Answer and explanation
Correct answer: B = {1, 3, 5, 7, 9}
The set-builder condition requires x to be both a natural number and odd, with x less than 10. The odd natural numbers below 10 are 1, 3, 5, 7, and 9, so the roster form is B = {1, 3, 5, 7, 9}. Option B contains even numbers, option C includes non-odd values, and option D includes 11, which fails x < 10. Thus A is correct.
Frequently asked questions
What is the correct answer to this question?
B = {1, 3, 5, 7, 9}
Why is this the correct answer?
The set-builder condition requires x to be both a natural number and odd, with x less than 10. The odd natural numbers below 10 are 1, 3, 5, 7, and 9, so the roster form is B = {1, 3, 5, 7, 9}. Option B contains even numbers, option C includes non-odd values, and option D includes 11, which fails x < 10. Thus A is correct.
Which subject and chapter does this question cover?
This is a Class 9 Mathematics question. Chapter: Common Questions. Topic: General chapter practice.
