Kode #108: hints & solution
Here's the clue board for Kode #108. 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.
- 16509▲1●1
- 22569▲0●2
- 37921▲0●2
- 41342▲0●2
- 57461▲0●0
Spoiler-free hints
- 2 of the four digits are even.
- The four digits add up to 14.
- Just one digit is 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 (7 4 6 1) has no marks at all, so 7, 4, 6, and 1 are not in the code.
- Row 3 (7 9 2 1) has 2 marks still unexplained, and only 2 digits are left undecided: 9 and 2. So both are in the code.
- Row 2 (2 5 6 9) has 2 marks, already accounted for by 2 and 9. That rules out 5.
- Row 1 (6 5 0 9) has one mark still unexplained, and only one digit is left undecided: 0. So it is in the code.
- Row 4 (1 3 4 2) has one mark still unexplained, and only one digit is left undecided: 3. So it is in the code.
- That makes all four digits of the code: 0, 2, 3, and 9. Every other digit is out, which also rules out 8.
- Row 1 (6 5 0 9) has one digit in the right spot. Since row 2 rules out the 9 in position 4, it has to be the 0 in position 3.
- The 2 has only one spot left: position 2 (row 2 rules out position 1, row 4 rules out position 4, and position 3 is already 0).
- The 9 has only one spot left: position 1 (row 2 rules out position 4, position 2 is already 2, and position 3 is already 0).
- That leaves the 3 for position 4.
That cracks it: the code is 9203.