Question

if n (A) = 20,n(B)=28 and n (A U B)=36 then n(A⋂B)=?
->(AUB)=n(A)+.....-n(A⋂B)
36 =......+28-n(A⋂B)
......= 48-n(A⋂B)
:.n(A⋂B)=48-36
:.n(A⋂B)=......
​

Answer 1

$\huge\mathfrak\red {Answer }$

IF A and B be two finite set such that it is given,

⟹ n{A}=20 n{B}=28 n{A∪B}=36 n{A∩B}=?

n{A∪B}= n{A}+ n{B} - n{A∩B}

→36=20+28 -n{A∩B}

→36=48 - n{A∩B}

→n{A∩B}=48-36

→n{A∩B}= 12