Question

${\left[\right(A^{\prime }\cup B^{\prime })-A]}^{\prime }$=___

• A. A
• B. B
• C. B - A
• D. A - B

Answer 1

The correct option is A

A

${\left[\right(A^{\prime }\cup B^{\prime })-A]}^{\prime }=\left[\right(A^{\prime }\cup B^{\prime })\cap A^{\prime }{]}^{\prime }(\because A-B=A\cap B^{\prime })=[{(A\cap B)}^{\prime }\cap A^{\prime }{]}^{\prime }(\because A^{\prime }\cup B^{\prime }={(A\cap B)}^{\prime })=[{(A\cap B)}^{\prime }{]}^{\prime }\cup {\left(A^{\prime }\right)}^{\prime }(\because A^{\prime }\cup B^{\prime }={(A\cap B)}^{\prime })=(A\cap B)\cup A=A$