Kode #25: hints & solution
Here's the clue board for Kode #25. Start with the spoiler-free hints. If you're still stuck, the full step-by-step solution is below, hidden until you open it.
The clue board
Each row is a guess that's already been graded. ▲ means a right digit in the right spot; ● means a right digit in the wrong spot.
- 18026▲1●1
- 29326▲0●1
- 38912▲1●0
- 45793▲0●2
- 51976▲0●0
Spoiler-free hints
- 2 of the four digits are even.
- The four digits add up to 16.
- 2 of the digits are 5 or higher.
Try the hints first. The solution below walks through every deduction.
Step-by-step solution
Every Kode can be cracked by pure deduction, with no guessing. This board falls in 10 logical steps. Open the solution to follow them one at a time.
Show the solution · reveals the code
When a row "rules out" a position, it shows that digit there but its ▲ marks are already used up (or it has none), so the digit can't sit there.
- Row 5 (1 9 7 6) has no marks at all, so 1, 9, 7, and 6 are not in the code.
- Row 4 (5 7 9 3) has 2 marks still unexplained, and only 2 digits are left undecided: 5 and 3. So both are in the code.
- Row 2 (9 3 2 6) has one mark, already accounted for by 3. That rules out 2.
- Row 1 (8 0 2 6) has 2 marks still unexplained, and only 2 digits are left undecided: 8 and 0. So both are in the code.
- That makes all four digits of the code: 0, 3, 5, and 8. Every other digit is out, which also rules out 4.
- Row 3 (8 9 1 2) has one digit in the right spot, and the 8 in position 1 is its only digit in the code, so it's locked in.
- Row 1 (8 0 2 6) has only one digit in the right spot, already accounted for by the 8 in position 1. So the 0 isn't in position 2.
- The 3 has only one spot left: position 3 (row 2 rules out position 2, row 4 rules out position 4, and position 1 is already 8).
- The 0 has only one spot left: position 4 (row 1 rules out position 2, position 1 is already 8, and position 3 is already 3).
- That leaves the 5 for position 2.
That cracks it: the code is 8530.