Crack the code? Puzzle

Question

Crack the code . Can you. Then you will be genius.

What is the source of this puzzle? Or did you make it yourself? — Rand al'Thor, Apr 06 '20 at 12:56
So, I found the likely source to this edited pic. https://listquiz.blogspot.com/2020/03/find-code-and-unlock-it.html - EDIT: It actually looks like it's from a different source as the above copied pic has curved corners; maybe a mobile app? How do we handle these? — MacGyver88, Apr 07 '20 at 12:09

score 3 · Answer 1 · answered Apr 06 '20 at 12:59

3

The number is

$6824$.

Explanation:

From the fourth clue, one of $3817$ is correct and well placed. It can't be $1$ (that would contradict the third clue) or $3$ or $7$ (that would contradict the second clue), so it must be $8$ in the second place.
From the second clue, two numbers are correct and well placed. We know $3$ and $7$ are not in the solution, so it must be $6$ in the first place and $4$ in the last place.
Now the third clue is valid with $6$ correct but wrongly placed.
Finally, in the first clue, $4$ is wrongly placed, and $3$ and $9$ are not part of the solution, so the last number must be $2$ in the third place.

answered Apr 06 '20 at 12:59

Rand al'Thor

2

Rand, you should be an experienced enough PSE member to know better than to answer questions that are obviously going to be put on hold for lack of attribution. – Gareth McCaughan Apr 06 '20 at 13:38
1

@Gareth I'm here to have fun solving puzzles. There's no harm in that: it's not plagiarism since the OP isn't claiming to have made it themselves, and indeed there's no proof they didn't make it themselves. – Rand al'Thor Apr 06 '20 at 13:45
1

@DavyM Worth leaving that as a comment on the question - it might influence people to reopen-vote based on "benefit of the doubt" arguments. – Rand al'Thor Apr 06 '20 at 20:13

1 Answers1