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.
B ends in A ends in
2 6
4 2
6 8
8 4
0 0 (a repetition of a digit)
Single digits don't work for B, so it must be two digits. We'd preferably want a high 10's digit so the carry could be a 2.
82 results in 246, repeating a 2
84 results in 252, an odd 5 and repetition of 2
86 results in 258, an odd 5 and repetition of 8
62 ... 186: much too small, go straight to
68 gives 204
B = 68
A = 204

Posted by Charlie
on 20180115 10:01:01 