Let R be a relation on the set N defined by aRb if a + 2b = 10. The domain of R is:

Let R be a relation on the set N defined by aRb if a + 2b = 10. The domain of R is:

• A. {2, 4, 6, 8}
• B. {1, 2, 3, 4}
• C. {2, 4, 6}
• D. {1, 2, 3, 4, 5}

Answer: A) {2, 4, 6, 8}

Explanation: For a, b ∈ N, a = 10 − 2b. b = 1 → a = 8; b = 2 → a = 6; b = 3 → a = 4; b = 4 → a = 2; b = 5 → a = 0 ∉ N. Domain = {8, 6, 4, 2} = {2, 4, 6, 8}.