1. Let R be an equivalence relation on a finite set A having n elements. Then, the number of ordered pairs in R is

2. For real numbers x and y, we write xRy ⇔ x – y + √2 is an irrational number. Then, the relational R is

3. Let R be a relation on the set N be defined by {(x, y) | x, y ∈ N, 2x + y = 41}. Then R is

4. Which one of the following relations on R is an equivalence relation?

5. Let R be a relation on the set N of natural numbers denoted by nRm ⇔ n is a factor of m (i.e. n | m). Then, R is