If A = {x ∈ N : x ≤ 9 and x is odd} and B = {x ∈ N : x < 8 and x is prime}, what is A ∩ B?
Answer and explanation
Correct answer: {3, 5, 7}
Assuming N contains the positive natural numbers, the odd numbers not exceeding 9 are A = {1, 3, 5, 7, 9}. The prime numbers less than 8 are B = {2, 3, 5, 7}; 1 is not prime. The elements common to both lists are 3, 5, and 7. Hence A ∩ B = {3, 5, 7}. Option B is A itself, and option C is B itself, so neither is the intersection.
Frequently asked questions
What is the correct answer to this question?
{3, 5, 7}
Why is this the correct answer?
Assuming N contains the positive natural numbers, the odd numbers not exceeding 9 are A = {1, 3, 5, 7, 9}. The prime numbers less than 8 are B = {2, 3, 5, 7}; 1 is not prime. The elements common to both lists are 3, 5, and 7. Hence A ∩ B = {3, 5, 7}. Option B is A itself, and option C is B itself, so neither is the intersection.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Sets. Topic: Operations on Sets (Union, Intersection, Difference).
