Set Theory

[nycmath]

See attachment.

[Math Tutor]

A = factors of 15 = {1, 3, 5, 15}
B = primes less than 10 = {2, 3, 5, 7}
C = even numbers less than 9 = {2, 4, 6, 8}

First the union: A ∪ B = {1, 2, 3, 5, 7, 15}

Now intersect that with C — keep only the numbers that are in both. The odd elements 1, 3, 5, 7, 15 are not in C, and the only even one is 2.

(A ∪ B) ∩ C = {2}

So the answer is D.

[nycmath]

A = factors of 15 = {1, 3, 5, 15}
B = primes less than 10 = {2, 3, 5, 7}
C = even numbers less than 9 = {2, 4, 6, 8}

First the union: A ∪ B = {1, 2, 3, 5, 7, 15}

Now intersect that with C — keep only the numbers that are in both. The odd elements 1, 3, 5, 7, 15 are not in C, and the only even one is 2.

(A ∪ B) ∩ C = {2}

So the answer is D.

Thank you. I find set theory interesting.