Question

A Venn diagram is shown below:

What are the elements of (A ∩ B) ' ?

A. {3,4,5,6}
B. {1,2,5,6}
C. {1,2,3,4}
D. {1,2,3,4,5}

I was under the assumption that the intersection of 2 sets was the Elements present in both sets so i thought the answer was just {1,2} but apparently not. Anyone who can answer please explain where my mistake was.

Answer 1

the elements of A are {1,2,3,4} while that of B are {1,2,5,6}. the problem asks for (A ∩ B) ' which means that we take the alternate universe of (A ∩ B). (A ∩ B) which is composed of elements that are present in both sets which are {1,2}. (A ∩ B)' then should be {3,4,5,6}