What is the possible number of reflexive relations on a set of 5 elements?

Total ordered pairs on a set of 5 elements = 5×5=25

For a relation to be reflexive , all diagonal pairs (1,1),(2,2),(3,3),(4,4),(5,5) must be included → 5 fixed pairs

Remaining pairs = 25−5=20

Each remaining pair can be chosen or not chosen

Number of reflexive relations=2 20