College Liberal Arts Math Sets questions

Question

Given the following definitions:

U = {1, 2, 3, 4, 5, 6, 7}

A = {1, 2, 4, 5}

B = {1, 3, 5, 7}

How many elements are in A' ∩ B' ?

Answer 1

A' = U - A = {1,2,3,4,5,6,7} - {1,2,4,5} = {3,6,7}

B' = U - B = {1,2,3,4,5,6,7} - {1,3,5,7} = {2,4,6}

 

The ∩ operation (AND or intersection) includes all elements that are members of both sets (A' and B'):

 

A' ∩ B' = {3,6,7} ∩ {2,4,6} = {6}

 

So there is one elements in A' ∩ B'.