Question

The relation R defined on the set of natural numbers as {(a, b) : a differs from b by 3} is given by

(A) {(1, 4, (2, 5), (3, 6), ...}

(B) {(4, 1), (5, 2), (6, 3), ...}

(C) {(1, 3), (2, 6), (3, 9), …}

(D) of these

Answer 1

Correct option**(B) {(4, 1), (5, 2), (6, 3), ...}**

Explanation :

R = {(a,b): a,b ∈ N, a - b = 3} ={((n + 3),n) : n ∈ N}

= {(4 1, ),(5 2, ),(6 3, ),...}.