Question

If n (A) = 15, n (A$\cup$B ) = 29, n (A $\cap$ B) = 7 then n (B) = ?

Answer 1

We have,

n (A) = 15, n (A$\cup$B ) = 29, n (A $\cap$ B) = 7

Since, n (B) = n (A$\cup$B ) + n (A $\cap$ B) $-$ n (A) = $29+7-15$

So, n (B) = 21