Question

Let A and B be two sets in the same universal set. Then A - B =

• A. $A\cap B$
• B. $A\cap B\text{'}$
• C. $A\text{'}\cap B$
• D. $A-(A\cap B)$

Answer 1

Answer: (B), (D)

$A-(A\cap B)$

A - B is a set of all elements belonging to A but not B.
$A\cap B\text{'}$ implies the intersection of all the elements of A with all the elements that are not included in B.
therefore,
$A\cap B\text{'}=A-B$
Also, A - B can computed by removing common elements of
A and B from the set A.
Therefore,
$A-(A\cap B)=A-B$