Difficulty: Easy
Correct Answer: 2, 5 and 8
Explanation:
Given data
Concept / Approach
Step-by-step condition
Digit sum = 5 + * + 2 = 7 + *Require 7 + * ≡ 0 (mod 3) ⇒ * ≡ 2 (mod 3)Digits 0–9 satisfying * ≡ 2 (mod 3): {2, 5, 8}Therefore the acceptable values are 2, 5 and 8.
Common pitfalls
Final Answer
Valid digits: 2, 5 and 8.
Discussion & Comments