Which elements belong to B = {x : x is a positive divisor of 36 and x is not prime}?
Answer and explanation
Correct answer: B = {1, 4, 6, 9, 12, 18, 36}
First list the positive divisors of 36: 1, 2, 3, 4, 6, 9, 12, 18 and 36. The prime divisors in this list are 2 and 3, so they must be removed. The number 1 is not prime because a prime number has exactly two positive divisors, whereas 1 has only one. All remaining divisors are composite or 1, giving option A.
Frequently asked questions
What is the correct answer to this question?
B = {1, 4, 6, 9, 12, 18, 36}
Why is this the correct answer?
First list the positive divisors of 36: 1, 2, 3, 4, 6, 9, 12, 18 and 36. The prime divisors in this list are 2 and 3, so they must be removed. The number 1 is not prime because a prime number has exactly two positive divisors, whereas 1 has only one. All remaining divisors are composite or 1, giving option A.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Sets. Topic: Sets and their representations.
