Determine the cardinal number of the set. X={4,5,8,10,11,12,13,14,15,17} X = { 4 , 5 , 8 , 10 , 11 , 12 , 13 , 14 , 15 , 17 }

Answer 1

The cardinal number of a set is just the number of unique (non-duplicate) members of the set. So just count them, excluding any duplicates. For example, the cardinal number of the set A = {2, 3, 5, 5, 9} is four. Count the 2, the 3, one of the 5s but not the duplicate 5, and the 9, giving a cardinal number of 4 unique elements.

So how many unique members are in your set X?