A relation R is defined on the set of natural numbers N by aRb if GCD(a, b) = 1. Then R is:

A relation R is defined on the set of natural numbers N by aRb if GCD(a, b) = 1. Then R is:

• A. Reflexive and symmetric
• B. Symmetric only
• C. Transitive only
• D. Equivalence

Answer: B) Symmetric only

Explanation: Not reflexive because GCD(2,2) = 2 ≠ 1. It is symmetric because GCD(a,b) = GCD(b,a). Not transitive because GCD(2,3) = 1 and GCD(3,2) = 1, but GCD(2,2) ≠ 1.