Determine with proof the number of ordered triples $\displaystyle (A_1, A_2, A_3) $ of sets which have the property (i) $\displaystyle A_1 \cup A_2 \cup A_3 = \{1,2,3,4,5,6,7,8,9,10 \} $ and (ii) $\displaystyle A_1 \cap A_2 \cap A_3 = \emptyset $. So basically this means that all the sets are disjoint.