Answer to 3 1 4 1 5 = ? Puzzle
The answer is 7.
The numbers on the right are calculated according the following formula:
X = (3A + 1B + 4C + 1D +5E) mod 9
where A, B, C, D, E are the numbers on the left, in order.
I found the solution (after trying lots of other fruitless things) by noticing that the when the rightmost or leftmost numbers incremented while the other numbers were constant, the result seemed to cycle as if it rolled over at 9. After that, I quickly found that
X = (3A + 1B + 1C + 1D +1E) mod 9
worked for some cases, then found that
X = (1A + 1B + 1C + 1D +5E) mod 9
worked for other cases. Then I tried
X = (3A + 2B + 2C + 2D +5E) mod 9
and that worked for most of the cases. That’s when I noticed that the final problem was 3 1 4 1 5 and that maybe THOSE were the right coefficients.
