Kode #173: hints & solution
Here's the clue board for Kode #173. 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.
- 16308▲1●1
- 25928▲0●2
- 37219▲0●2
- 42869▲1●2
- 57250▲0●0
Spoiler-free hints
- 2 of the four digits are even.
- The four digits add up to 24.
- 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 5 0) has no marks at all, so 7, 2, 5, and 0 are not in the code.
- Row 2 (5 9 2 8) has 2 marks still unexplained, and only 2 digits are left undecided: 9 and 8. So both are in the code.
- Row 3 (7 2 1 9) has one mark still unexplained, and only one digit is left undecided: 1. So it is in the code.
- Row 4 (2 8 6 9) has one mark still unexplained, and only one digit is left undecided: 6. So it is in the code.
- Row 1 (6 3 0 8) has 2 marks, already accounted for by 6 and 8. That rules out 3.
- That makes all four digits of the code: 1, 6, 8, and 9. Every other digit is out, which also rules out 4.
- Row 1 (6 3 0 8) has one digit in the right spot. Since row 2 rules out the 8 in position 4, it has to be the 6 in position 1.
- Row 4 (2 8 6 9) has one digit in the right spot. Since the 6 is already in position 1 and row 3 rules out the 9 in position 4, it has to be the 8 in position 2.
- The 1 has only one spot left: position 4 (row 3 rules out position 3, position 1 is already 6, and position 2 is already 8).
- That leaves the 9 for position 3.
That cracks it: the code is 6891.