1.
The set S={1,2,3,,12}S = \{1, 2, 3, \dots, 12\} is to be partitioned into three sets A,B,CA, B, C of equal size. Thus ABC=SA \cup B \cup C = S, AB=BC=CA=A \cap B = B \cap C = C \cap A = \emptyset, then the number of ways to partition SS are