Q.

Let R be a relation on the set N of natural numbers defined by nRm if n divides m. Then R is:

1 Reflexive and symmetric  
2 Transitive and symmetric  
3 Equivalence  
4 Reflexive, transitive but not symmetric  

Ans.

(4)

Ans.      Reflexive, transitive but not symmetric

Explanation:

Since n divides n,∀n∈N,R is reflexive. R is not symmetric since for 3,6∈N, 3R6≠6R3.

R is transitive since for n,m,r, whenever nm and mr⇒nr, i.e., n divides m and m divides r, then n will divide r.