Question

Let A = {x : x is a natural number and a factor of 15}

B = {x : x is a natural number and less than 5}

Find A ∪ B and A ∩ B.

• A. A ∩ B = {1, 3}
• B. A ∪ B = {1, 2, 3, 4, 5,15}
• C. A ∩ B = {1, 2, 4}
• D. A ∪ B = {1, 1, 2, 2, 3, 3, 4, 5, 6, 9,18}

Answer 1

Answer: (A), (B)

The correct options are
A A ∩ B = {1, 3}
B A ∪ B = {1, 2, 3, 4, 5,15}

A = {1, 3, 5, 15 }

B = {1, 2, 3, 4 }

Therefore, A ∩ B = {1, 3}
and A ∪ B = {1, 2, 3, 4, 5, 15}