MYSTERY CODEmedium
Crack the 3-digit code.
All three digits are different.
WHAT'S THE CODE?
Clues
- 607One digit is correct and in the right place.
- 368One digit is correct but in the wrong place.
- 462Two digits are correct, both in the wrong places.
- 259No digit is correct.
- 312One digit is correct but in the wrong place.
Answer
641
Why it works
Eliminating 2, 5, and 9 identifies 6 and 4 as code digits; the placement clues then force 6 — 4 — 1.
- From 259, the digits 2, 5, and 9 are not in the code.
- In 462, 2 is excluded, so 4 and 6 are the two correct digits, both misplaced. Thus 4 is not first and 6 is not second.
- The 607 clue has one correct digit in the right place. Since 6 is known to be in the code, it must be that digit, fixing 6 first; 0 and 7 are absent.
- In 368, the one correct digit is 6, but it is shown second, confirming its position is wrong in that clue and excluding 3 and 8.
- In 312, 3 and 2 are excluded, so 1 is the one correct digit and is misplaced from second. With 6 first and 4 not first, 4 must be second and 1 third: 641.