9514 1404 393
Answer:
15
Step-by-step explanation:
For numbers to be divisible by 3, the sum of their digits must be divisible by 3.
This means we require ...
(7 + 1 + 2 + 3 + A + 3 + 2) mod 3 = 0 ⇒ A mod 3 = 0
(2 + B + 2 + 5 + 6 + 8 + 9) mod 3 = 0 ⇒ (2+B) mod 3 = 0 ⇒ B mod 3 = -2
(4 + 5 + 0 + A + B + C + 6) mod 3 = 0 ⇒ (C -2) mod 3 = 0
Possible values of C are 2, 5, 8. Their sum is 15.
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For example, let A=0, B=1, C=2. Then we have ...
7123032 = 2374344×3
2125689 = 708563×3
4500126 = 1500042×3
