Let R be an equivalence relation on the set $A= \{1,2,3,4,5\}$ given by R= {(x, y):2 divides (x - y)}. Then equivalence class of 3 is:

$\{1,5\}$ $\{1,3,5\}$ $\{3,5\}$ $\{2,4\}$

$\{1,3,5\}$

$A= \{1,2,3,4,5\}$  R= {(x, y):2 divides (x - y)} for any $x∈A$ $(x-x)=0$ (divisible by 2) $⇒(x,x)∈R$ for all $x∈A$  (Reflexive relation) so for 3 → its equivalence relation is $\{1,3,5\}$ (1-3)(3-3)(5-3) all divisible by 2