Kode #27: hints & solution
Here's the clue board for Kode #27. 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.
- 13810▲1●1
- 23218▲0●2
- 31724▲0●2
- 49270▲0●1
- 57360▲0●0
Spoiler-free hints
- 2 of the four digits are even.
- The four digits add up to 22.
- 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 (7 3 6 0) has no marks at all, so 7, 3, 6, and 0 are not in the code.
- Row 1 (3 8 1 0) has 2 marks still unexplained, and only 2 digits are left undecided: 8 and 1. So both are in the code.
- Row 2 (3 2 1 8) has 2 marks, already accounted for by 1 and 8. That rules out 2.
- Row 3 (1 7 2 4) has one mark still unexplained, and only one digit is left undecided: 4. So it is in the code.
- Row 4 (9 2 7 0) has one mark still unexplained, and only one digit is left undecided: 9. So it is in the code.
- That makes all four digits of the code: 1, 4, 8, and 9. Every other digit is out, which also rules out 5.
- Row 1 (3 8 1 0) has one digit in the right spot. Since row 2 rules out the 1 in position 3, it has to be the 8 in position 2.
- The 1 has only one spot left: position 4 (row 3 rules out position 1, row 2 rules out position 3, and position 2 is already 8).
- The 9 has only one spot left: position 3 (row 4 rules out position 1, position 2 is already 8, and position 4 is already 1).
- That leaves the 4 for position 1.
That cracks it: the code is 4891.