Kode #80: hints & solution
Here's the clue board for Kode #80. 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.
- 14510▲1●1
- 24561▲0●2
- 36254▲0●2
- 47869▲0●2
- 57248▲0●0
Spoiler-free hints
- 2 of the four digits are even.
- The four digits add up to 20.
- 3 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 2 4 8) has no marks at all, so 7, 2, 4, and 8 are not in the code.
- Row 3 (6 2 5 4) has 2 marks still unexplained, and only 2 digits are left undecided: 6 and 5. So both are in the code.
- Row 2 (4 5 6 1) has 2 marks, already accounted for by 5 and 6. That rules out 1.
- Row 1 (4 5 1 0) has one mark still unexplained, and only one digit is left undecided: 0. So it is in the code.
- Row 4 (7 8 6 9) 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: 0, 5, 6, and 9. Every other digit is out, which also rules out 3.
- Row 1 (4 5 1 0) has one digit in the right spot. Since row 2 rules out the 5 in position 2, it has to be the 0 in position 4.
- The 5 has only one spot left: position 1 (row 2 rules out position 2, row 3 rules out position 3, and position 4 is already 0).
- The 6 has only one spot left: position 2 (row 2 rules out position 3, position 1 is already 5, and position 4 is already 0).
- That leaves the 9 for position 3.
That cracks it: the code is 5690.