MYSTERY CODEmedium
Crack the 3-digit code.
All three digits are different.
WHAT'S THE CODE?
Clues
- 734One digit is correct and in the right place.
- 817One digit is correct but in the wrong place.
- 974Two digits are correct, both in the wrong places.
- 548No digit is correct.
- 096One digit is correct but in the wrong place.
Answer
729
Why it works
The no-match clue removes 5, 4, and 8; the remaining clues then fix 7 first and 9 last, leaving 2 in the middle.
- From 548, the digits 5, 4, and 8 are not in the code.
- In 974, 4 is excluded, so 9 and 7 are the two correct digits. Both are misplaced there: 9 is not first and 7 is not second.
- The 734 clue has only 7 or 3 available, and it says one digit is correct and correctly placed. Since 7 is known to be in the code and cannot be second, 7 must be first; 3 is not used.
- In 817, 8 is excluded and 7 is the one correct digit, but it is shown third. That confirms 7 is misplaced in that clue and 1 is not used.
- In 096, the one correct misplaced digit is 9. It is shown second, so it cannot be second; with 7 fixed first, 9 must be third. The only open digit is 2, giving 729.