Chapter 2 - Set Theory - 2.3 Venn Diagrams and Set Operations - Exercise Set 2.3 - Page 81: 11

C' = {2,4,6,8,10....18,20}

U = {1,2,3,4...20} C = {1,3,5,7,9....19} The set C' contains the elements that are not present in the set C. The elements of set C i.e. 1,3,5,7....19 must not be present in set C. The elements of C' are 2,4,6,8,....20. Therefore C' = {2,4,6,8,10....18,20}