Kode #169: hints & solution
Here's the clue board for Kode #169. 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.
- 14162▲1●1
- 28062▲0●1
- 39638▲0●2
- 46870▲0●0
- 53621▲0●2
Spoiler-free hints
- 2 of the four digits are even.
- The four digits add up to 18.
- 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 (6 8 7 0) has no marks at all, so 6, 8, 7, and 0 are not in the code.
- Row 2 (8 0 6 2) has one mark still unexplained, and only one digit is left undecided: 2. So it is in the code.
- Row 3 (9 6 3 8) has 2 marks still unexplained, and only 2 digits are left undecided: 9 and 3. So both are in the code.
- Row 5 (3 6 2 1) has 2 marks, already accounted for by 3 and 2. That rules out 1.
- Row 1 (4 1 6 2) has one mark still unexplained, and only one digit is left undecided: 4. So it is in the code.
- That makes all four digits of the code: 2, 3, 4, and 9. Every other digit is out, which also rules out 5.
- Row 1 (4 1 6 2) has one digit in the right spot. Since row 2 rules out the 2 in position 4, it has to be the 4 in position 1.
- The 2 has only one spot left: position 2 (row 5 rules out position 3, row 2 rules out position 4, and position 1 is already 4).
- The 3 has only one spot left: position 4 (row 3 rules out position 3, position 1 is already 4, and position 2 is already 2).
- That leaves the 9 for position 3.
That cracks it: the code is 4293.