How many reflexive relations are there on a set with $3$ elements?

Determine whether the following relation $R$ in the set $A = \{1, 2, 3, 4, 5, 6\}$ defined by $R = \{(x, y) : y \text{ is divisible by } x\}$ is reflexive,symmetric,and transitive.

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

Let $R$ be a reflexive relation on a finite set $A$ containing $n$ elements,and let $R$ contain $m$ ordered pairs. Then,

Let $A = \{2, 3, 5, 7, 9\}$. Let $R$ be the relation on $A$ defined by $xRy$ if and only if $2x \le 3y$. Let $l$ be the number of elements in $R$,and $m$ be the minimum number of elements required to be added in $R$ to make it a symmetric relation. Then $l + m$ is equal to:

Let $R$ be a relation from $Q$ to $Q$ defined by $R = \{(a, b) : a, b \in Q \text{ and } a - b \in Z\}$. Show that $(a, b) \in R$ implies that $(b, a) \in R$.