Question

If n (A) = 5; n (A U B) = 9, n (A ^ B) = 2. Find n (B).​

Answer 1

$Given \: n(A) = 5 , \: n( A \cup B ) = 9$

$n( A \cap B) = 2 , \red{n(B) = ? }$

$\boxed { \pink { n(A)+n(B) = n(A\cup B) + n(A\cap B )}}$

$\implies 5 + n(B) = 9 + 2$

$\implies n(B) = 11 - 5$

$\implies n(B) = 6$

Therefore.,.

$\red{ n(B) }\green { = 6 }$

•••♪