U = {1, 2, 3, ..., 120}; A is the set of numbers divisible by 3, B by 4, and C by 12. Which relation is correct?
Answer and explanation
Correct answer: C = A ∩ B
A number is in A ∩ B exactly when it is divisible by both 3 and 4. Because lcm(3, 4) = 12, this condition is equivalent to being divisible by 12, which defines C. Thus C = A ∩ B. The union would include numbers divisible by only one of 3 or 4, while C is the smaller common set, so option A is the only correct relation.
Frequently asked questions
What is the correct answer to this question?
C = A ∩ B
Why is this the correct answer?
A number is in A ∩ B exactly when it is divisible by both 3 and 4. Because lcm(3, 4) = 12, this condition is equivalent to being divisible by 12, which defines C. Thus C = A ∩ B. The union would include numbers divisible by only one of 3 or 4, while C is the smaller common set, so option A is the only correct relation.
Which subject and chapter does this question cover?
This is a Class 12 Mathematics question. Chapter: Sets.