Question

Let n($\cup$)=700, n(A)=400, n(B)=300, n(A$\cap$B)=300. Then (A'$\cap$B') =

• A. 300
• B. 400
• C. 350
• D. 250

Answer 1

The correct option is A 300

$n\left(u\right)=700;n\left(A\right)=400$

$n\left(B\right)=300;n(A\cap B)=300$

$A^{\prime }\cap B^{\prime }=(A\cup B{)}^{\prime }$

$n(A\cup B)=n\left(A\right)+n\left(B\right)-n(A\cap B)$

$=400+300-300$

$=400$

$n(A^{\prime }\cap B^{\prime })=n\left(\right(A\cup B{)}^{\prime })=n(u)-n(A\cup B)$

$=700-400$

$=300$

$n(A^{\prime }\cap B^{\prime })=300$