Kode #140: hints & solution
Here's the clue board for Kode #140. 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.
- 15680▲1●1
- 22789▲0●2
- 30978▲1●1
- 47914▲1●1
- 57452▲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 4 5 2) has no marks at all, so 7, 4, 5, and 2 are not in the code.
- Row 2 (2 7 8 9) has 2 marks still unexplained, and only 2 digits are left undecided: 8 and 9. So both are in the code.
- Row 3 (0 9 7 8) has 2 marks, already accounted for by 9 and 8. That rules out 0.
- Row 1 (5 6 8 0) has one mark still unexplained, and only one digit is left undecided: 6. So it is in the code.
- Row 4 (7 9 1 4) 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: 1, 6, 8, and 9. Every other digit is out, which also rules out 3.
- Row 1 (5 6 8 0) has one digit in the right spot. Since row 2 rules out the 8 in position 3, it has to be the 6 in position 2.
- Row 3 (0 9 7 8) has one digit in the right spot. Since position 2 is already 6, it has to be the 8 in position 4.
- Row 4 (7 9 1 4) has one digit in the right spot. Since position 2 is already 6, it has to be the 1 in position 3.
- That leaves the 9 for position 1.
That cracks it: the code is 9618.