Let A = {x: x ∈ N ∧ x is a multiple of 2}; B = {x: x ∈ N ∧ x is a multiple of 5}; C = {x: x ∈ N ∧ x is a multiple of 10}; Describe the set (A ∩ B) ∩ C,
Correct Answer: C
Explanation:
A = {2, 4, 6,…}
B = {5, 10, 15,…}
C = {10, 20, 30,…}
∴ (A ∩ B) = {2, 4, 6…} ∩ {5, 10, 15,…} = {10, 20, 30,…} = C
∴ (A ∩ B) ∩ C = C ∩ C = C.
