Kode #139: hints & solution
Here's the clue board for Kode #139. 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.
- 16931▲1●1
- 22431▲0●1
- 37930▲0●2
- 48172▲0●0
- 51764▲0●2
Spoiler-free hints
- 3 of the four digits are even.
- The four digits add up to 19.
- 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 4 (8 1 7 2) has no marks at all, so 8, 1, 7, and 2 are not in the code.
- Row 5 (1 7 6 4) has 2 marks still unexplained, and only 2 digits are left undecided: 6 and 4. So both are in the code.
- Row 2 (2 4 3 1) has one mark, already accounted for by 4. That rules out 3.
- Row 1 (6 9 3 1) has one mark still unexplained, and only one digit is left undecided: 9. So it is in the code.
- Row 3 (7 9 3 0) has one mark still unexplained, and only one digit is left undecided: 0. So it is in the code.
- That makes all four digits of the code: 0, 4, 6, and 9. Every other digit is out, which also rules out 5.
- Row 1 (6 9 3 1) has one digit in the right spot. Since row 3 rules out the 9 in position 2, it has to be the 6 in position 1.
- The 4 has only one spot left: position 3 (row 2 rules out position 2, row 5 rules out position 4, and position 1 is already 6).
- The 0 has only one spot left: position 2 (row 3 rules out position 4, position 1 is already 6, and position 3 is already 4).
- That leaves the 9 for position 4.
That cracks it: the code is 6049.