Let A = {2, 3, 4, . . . , 30} and “∼” be defined on A × A by (a, b) ∼(c, d) iff ad = bc. The number of ordered pairs which are related to (4, 3) is:
Let A = {2, 3, 6, 8, 9, 11}, B = {1, 4, 5, 10, 15}. R on A × B: (a, b) R (c, d) iff 3ad −7bc is even. Then R is:
Among the relations \( S = \left\{(a, b) : a, b \in \mathbb{R} - \{0\},\ 2 + \frac{a}{b} > 0\right\} \) and \( T = \{(a, b) : a, b \in \mathbb{R},\ a^{2} - b^{2} \in \mathbb{Z}\} \),
Let $A=\{-2,-1,0,1,2,3,4\}$. Let $R$ be a relation on $A$ defined by $xRy$ if and only if $2x+y\leq2$. Let $l$ be the number of elements in $R$. Let $m$ and $n$ be the minimum number of elements required to be added in $R$ to make it reflexive and symmetric respectively. Then $l+m+n$ is equal to: