Answer : Given: n(A) = 3, n(B) = 4 and n(A ∩ B) = 2
- n(A × B) = n(A) × n(B)
⇒ n(A × B) = 3 × 4
⇒ n(A × B) = 12
- n(B × A) = n(B) × n(A)
⇒ n(B × A) = 4 × 3
⇒ n(B × A) = 12
(iii) n((A × B) ∩ (B × A)) = n(A × B) + n(B × A) – n((A × B) ???? (B × A)) n((A × B) ∩ (B × A)) = n(A × B) + n(B × A) – n(A × B) + n(B × A) n((A × B) ∩ (B × A)) = 0