Question

If n (A) = 20, n (B) = 28 and n (A$\cup$B) = 36 then n (A $\cap$ B) = ?

Answer 1

We have,

n (A) = 20, n (B) = 28 and n (A$\cup$B) = 36

Since, n (A $\cap$ B ) = n (A) + n (B) $-$ n (A $\cup$ B) = $20+28-36$

$\therefore$ n (A $\cap$ B ) = 12