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Kode #17: hints & solution

Here's the clue board for Kode #17. 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.

  • 12970▲1●1
  • 20627▲1●1
  • 34951▲0●2
  • 45741▲0●1
  • 55710▲0●0

Spoiler-free hints

  • 3 of the four digits are even.
  • The four digits add up to 21.
  • 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 9 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.

  1. Row 5 (5 7 1 0) has no marks at all, so 5, 7, 1, and 0 are not in the code.
  2. Row 1 (2 9 7 0) has 2 marks still unexplained, and only 2 digits are left undecided: 2 and 9. So both are in the code.
  3. Row 2 (0 6 2 7) has one mark still unexplained, and only one digit is left undecided: 6. So it is in the code.
  4. Row 3 (4 9 5 1) has one mark still unexplained, and only one digit is left undecided: 4. So it is in the code.
  5. That makes all four digits of the code: 2, 4, 6, and 9. Every other digit is out, which also rules out 3 and 8.
  6. Row 1 (2 9 7 0) has one digit in the right spot. Since row 3 rules out the 9 in position 2, it has to be the 2 in position 1.
  7. Row 2 (0 6 2 7) has one digit in the right spot. Since the 2 is already in position 1, it has to be the 6 in position 2.
  8. The 4 has only one spot left: position 4 (row 4 rules out position 3, position 1 is already 2, and position 2 is already 6).
  9. That leaves the 9 for position 3.

That cracks it: the code is 2694.

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