Question

if A and. B are two sets such that n(A)=115, n(B)=326,n(A-B)=47, then write n(A intersection B)​

Answer 1

Well,

$A-B=A-(A\cap B)$

So,

$n(A-B)=n(A)-n(A\cap B)\\\\\implies\ n(A\cap B)=n(A)-n(A-B)\\\\\implies\ n(A\cap B)=115-47\\\\\implies\ n(A\cap B)=68$