Kode #69: hints & solution
Here's the clue board for Kode #69. 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.
- 10735▲1●1
- 20485▲0●1
- 35102▲0●1
- 41058▲0●0
- 50597▲1●0
Spoiler-free hints
- 2 of the four digits are even.
- The four digits add up to 16.
- 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 4 (1 0 5 8) has no marks at all, so 1, 0, 5, and 8 are not in the code.
- Row 1 (0 7 3 5) has 2 marks still unexplained, and only 2 digits are left undecided: 7 and 3. So both are in the code.
- Row 2 (0 4 8 5) has one mark still unexplained, and only one digit is left undecided: 4. So it is in the code.
- Row 3 (5 1 0 2) has one mark still unexplained, and only one digit is left undecided: 2. So it is in the code.
- Row 5 (0 5 9 7) has one mark, already accounted for by 7. That rules out 9.
- That makes all four digits of the code: 2, 3, 4, and 7. Every other digit is out, which also rules out 6.
- Row 5 (0 5 9 7) has one digit in the right spot, and the 7 in position 4 is its only digit in the code, so it's locked in.
- Row 1 (0 7 3 5) has one digit in the right spot. Since the 7 is already in position 4, it has to be the 3 in position 3.
- The 4 has only one spot left: position 1 (row 2 rules out position 2, position 3 is already 3, and position 4 is already 7).
- That leaves the 2 for position 2.
That cracks it: the code is 4237.