U = {1, 2, 3, 4, 5, 6, 7}, A = {1, 2, 3} ও B = {2, 4, 6} হলে A' ∩ B' = কত?
সঠিক উত্তর: {5, 7}
ব্যাখ্যা: A' = U \ A = {1, 2, 3, 4, 5, 6, 7} \ {1, 2, 3} = {4, 5, 6, 7}.
B' = U \ B = {1, 2, 3, 4, 5, 6, 7} - {2, 4, 6} = {1, 3, 5, 7}.
.: A' ∩ B' = {4, 5, 6, 7} ∩ {1, 3, 5, 7} = {5, 7}.