Question

Relation \( R \) on the set \( A = \{1, 2, 3, \ldots, 13, 14\} \) defined as \( R = \{(x, y) : 3x - y = 0\} \) is:

• A. Reflexive, symmetric and transitive
• B. Reflexive and transitive but not symmetric
• C. Neither reflexive nor symmetric but transitive
• D. Neither reflexive nor symmetric nor transitive

Answer 1

The Correct Option is C

The given relation is \( R = \{(x, y) : 3x - y = 0\} \).

• Reflexivity: For \( R \) to be reflexive, \( (x, x) \) must satisfy \( 3x - x = 0 \) for all \( x \in A \). However, \( 3x - x = 2x \neq 0 \) for \( x \neq 0 \). 
  Hence, \( R \) is not reflexive.
• Symmetry: For \( R \) to be symmetric, if \( (x, y) \in R \), then \( (y, x) \) must also belong to \( R \). 
  Check: \[ 3x - y = 0 \implies 3y - x \neq 0 \text{ for } x \neq y. \] Hence, \( R \) is not symmetric.
• Transitivity: For \( R \) to be transitive, if \( (x, y) \in R \) and \( (y, z) \in R \), then \( (x, z) \) must also belong to \( R \). 
  Check: \[ 3x - y = 0 \text{ and } 3y - z = 0 \implies 3(3x) - z = 0 \implies 9x - z = 0, \] which satisfies the condition. Hence, \( R \) is transitive.

Thus, the relation \( R \) is neither reflexive nor symmetric but transitive.