Posted by Jen on .
This is so confusing :(
Given U = {10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20}, A = {12, 14, 16, 18, 20}, and B = {11, 13, 14, 15, 18, 19, 20}.
Find A′ ∩ B′. Do not skip to the answer. Show your work, finding A’, then B’ then find their intersection.

Mathgeometry 
MathMate,
A' is the same as UA, i.e. all the elements of A' must be in U but NOT in A.
So A'={10,11,13,15,...}
and
B'={10,12,...}
A'∩B' contains elements that are members of both A' and B', or
A'∩B' = {10,...}