Set, Relation and FunctionHard
Question
Let $A = \{ 2,3,5,7,9\}$. Let R be the relation on A defined by x Ry if and only if $2x \leq 3y$. Let $\mathcal{l}$ 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 $\mathcal{l} + m$ is equal to:
Options
A.23
B.25
C.21
D.27
Solution
$\ A = \{ 2,3,5,7,9\}$
$$\left. \ \begin{matrix} & y \geq \frac{2x}{3} \\ x = 2, & y = 2,3,5,7,9 \\ x = 3, & y = 2,3,5,7,9 \\ x = 5, & y = 5,7,9 \\ x = 7, & y = 5,7,9 \\ x = 9 & y = 7,9 \end{matrix} \right\rbrack \rightarrow \mathcal{l} = 18 $$to make it symmetric elements to be added are
$${\{(5,2),(7,2),(9,2),(5,3),(7,3),(9,3),(9,5)\} }{m = 7 }{\therefore\ \mathcal{l} + m = 25}$$
Create a free account to view solution
View Solution FreeMore Set, Relation and Function Questions
The median of a set of 9 distinct observations is 20.5. If each of the largest 4 observations of the set is increased by...The mean of the data set comprising of 16 observations is 16. If one of the observation valued 16 is deleted and three n...If A, B and C are any three sets, then A × (B ∪ C) is -...Let A = {a, b, c, d}, B = {b, c, d, e}. Then n[(A × B) (B × A)] is equal to -...If f(x) = ax2[x] - b{x}2, where [.] and {.} denotes greatest integer and fractional part function respectively, then whi...