MattyRx: This cache was located at Corndale Hall. It was attached underneath the steps that allowed entry to the hall. Unfortunately, on 28th Feb 2022, the whole hall was picked up in floodwater and washed away. Sadly, I'll archive this one. It was a special cache with a few good memories attached with the FTF. Anywho, if anyone is interested - here's how the puzzle goes:
+++++++++++++++++++++++++++++++++++++++++
Answer: 1 5 3
You can see from clue 4 that there are no 8, 4, or 9.
You can see from clue 5 that there is a 1 in either the first or second slot, and from clue 3 that it must be in the first slot. That means the code is [1][?][?].
7 cannot be the correct number from clue 1, since it would have to be in the wrong position for clue 2. We already know 9 is incorrect, so 3 must have to be correct, and it must be in the third slot.
This means the code is [1][?][3].
Finally, from the second clue, we can see that one number is correct but in the wrong place. It can't be 7, since we ruled that out already. It can't be 2, since that would be in the correct place. Therefore the code is 153.
+++++++++++++++++++++++++++++++++++++++++