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. None of these

Answer 1

The correct option is B

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

$R=\left\{\right(a,b):a,b\in N,a-b=3\}=\left\{\right((n+3),n):n\in N\}$

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