pls explain how to get answer and what is response. Previous response was incorrect.

Let S be the universal set, where: S = {1, 2, 3, ..., 18, 19, 20} Let sets A and B be subsets of S, where: Set A = {1, 3, 4, 7, 9, 12, 18, 19} Set B - {3, 5, 6, 7, 8, 10, 11, 13, 14, 16, 18, 20} Set C = {4, 5, 6, 7, 9, 10, 11, 12, 13, 14, 19} Find the number of elements in the set (A U B U C) n( A U B UC) = Find the number of elements in the set (An Bn C) n(AnBnC) = You may want to draw a Venn Diagram to help answer this