Q1 of 43 Page 16

If n(A) = 15, n(A ∪ B) = 29, n (A ∩ B) = 7 then n (B) = ?

Given: n(A ∪ B) = 29, n(A) = 15 and n (A ∩ B) = 7

As we know, n (A ∪ B) = n(A) + n(B) - n (A ∩ B)


⇒ 7 = 15 + n(B) – 29


⇒ n(B) = -14 - 7


⇒ n(B) = -21


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