Find two integers A & B, such that:
1. A=3*B
2. Both integers together use only even digits, all of them, each once.
Provide your reasoning.

Pen and paper (at most!) only.

Since there are 5 digits, A must be 3 digits and B must be 2 digits.
The location of the zero must be the middle digit of A.  It can't be a leading zero and it can't be in the one's digit of either number.
Since A is a multiple of 3, its other 2 digits must be (4,2) or (4,8).
The maximum possible B is 86, so the first digit of A must be 2.
So the only possible A is 204; then B is 68

Posted by Larry on 2018-01-15 15:46:25