If ABC and DEF are both 3-digit numbers such that A, B, C, D, E and F are distinct non-zero digits such that ABC + DEF = 1111, then what is the value of A + B + C + D + E + F ?
A
28
B
29
C
30
D
31
Correct Answer: Option D
Explanation
To solve this elegantly, we look at the addition vertically, just like we write it on paper:
A B C
+ D E F
-------
1 1 1 1
**Step 1: Analyze the Units Column (C + F)**
The result ends in