OK, think first of when the second statement is true, and then when it is false.
If "Only one of the inscriptions on these boxes is correct." is true, it follows that the other inscription is false, because only one is true.
If "Only one of the inscriptions on these boxes is correct" is false, the other cannot be true, as that would leave one true and one false.
Either way, the first inscription is false. Thus the deduction is that the coin is in the first box.
However, what is to stop her putting the coin in the second box?
(Sorry about the typo.)
If "Only one of the inscriptions on these boxes is correct." is true, it follows that the other inscription is false, because only one is true.
If "Only one of the inscriptions on these boxes is correct" is false, the other cannot be true, as that would leave one true and one false.
Either way, the first inscription is false. Thus the deduction is that the coin is in the first box.
However, what is to stop her putting the coin in the second box?
(Sorry about the typo.)
