Kode #109: hints & solution
Here's the clue board for Kode #109. 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.
- 16470▲1●1
- 26073▲0●2
- 39632▲0●2
- 44513▲0●1
- 55273▲0●0
Spoiler-free hints
- 2 of the four digits are even.
- The four digits add up to 16.
- 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 (5 2 7 3) has no marks at all, so 5, 2, 7, and 3 are not in the code.
- Row 2 (6 0 7 3) has 2 marks still unexplained, and only 2 digits are left undecided: 6 and 0. So both are in the code.
- Row 1 (6 4 7 0) has 2 marks, already accounted for by 6 and 0. That rules out 4.
- Row 3 (9 6 3 2) has one mark still unexplained, and only one digit is left undecided: 9. So it is in the code.
- Row 4 (4 5 1 3) has one mark still unexplained, and only one digit is left undecided: 1. So it is in the code.
- That makes all four digits of the code: 0, 1, 6, and 9. Every other digit is out, which also rules out 8.
- Row 1 (6 4 7 0) has one digit in the right spot. Since row 2 rules out the 6 in position 1, it has to be the 0 in position 4.
- The 6 has only one spot left: position 3 (row 2 rules out position 1, row 3 rules out position 2, and position 4 is already 0).
- The 9 has only one spot left: position 2 (row 3 rules out position 1, position 3 is already 6, and position 4 is already 0).
- That leaves the 1 for position 1.
That cracks it: the code is 1960.