(b) : Given relation R such that R = {(x,y) ∈ W × W ∣ the word x and y have atleast one letter in common} where W denotes set of words in English dictionary Clearly (x,x) ∈ R ∀ x in W ∴(x,x) has every letter common ∴ R is reflexive Let (x,y) ∈ R then (y,x) ∈ R as x and y have atleast one letter in common. ⇒ R is symmetric. But R is not transitive ∴ Let x = DON,y = NEST, z = SHE then (x,y) ∈ R and (y,z) ∈ R. But (x,z) ∈/ R. ∴ R is reflexive, symmetric but not transitive.