If Q = {x : x is a digit and x is prime}, which is the roster form of Q?
Answer and explanation
Correct answer: Q = {2, 3, 5, 7}
The governing concept is classifying the decimal digits 0 through 9 by primality. A prime number has exactly two positive divisors, 1 and itself. Among the digits, 2, 3, 5, and 7 satisfy this definition. The digit 1 is not prime, 0 is neither prime nor composite, and 9 is composite because it is divisible by 3. Therefore the roster form is {2,3,5,7}, so A is correct.
Frequently asked questions
What is the correct answer to this question?
Q = {2, 3, 5, 7}
Why is this the correct answer?
The governing concept is classifying the decimal digits 0 through 9 by primality. A prime number has exactly two positive divisors, 1 and itself. Among the digits, 2, 3, 5, and 7 satisfy this definition. The digit 1 is not prime, 0 is neither prime nor composite, and 9 is composite because it is divisible by 3. Therefore the roster form is {2,3,5,7}, so A is correct.
Which subject and chapter does this question cover?
This is a Class 12 Mathematics question. Chapter: Sets.
