Five metal pieces, made of gold, silver, bronze, platinum, and nickel respectively, were placed in five safes, numbered from 1 to 5. Each safe contains one piece, and the problem is to figure out which piece is in which safe. On the door of each safe is written a piece of information. Of the five pieces of information, four are false, and the only true one is the one that appears on the door of the safe that contains the gold piece. The information on the doors of the safes is as follows.

Safe 1: The gold is in safe 2 or 3.

Safe 2: The silver is in safe 1.

Safe 3: The bronze is not here.

Safe 4: The nickel is in the safe whose number is one less than the one that contains the gold.

Safe 5: The platinum is in the safe whose number is one more than the one that contains the bronze.
The first information is certainly false, because if it were true, the gold would be in chest 2 or 3, but it should be in chest 1 itself for the first information to be true. This contradiction shows that the gold is not in chest 2 or 3. Since the information on the door of chest 1 is false, we conclude that the other is also not in it. The second information is certainly false, because if it were true, the gold would be in chest 2, which is incorrect. Therefore, the first and second pieces of information are false. Hence, the gold is not in chest 1, nor in 2 or 3, and the silver is not in chest 1.

The only remaining possibilities for the gold are chests 4 or 5. If the gold were in chest 4,

![](https://cdn.mathpix.com/cropped/2024_05_01_30c9a294a58a6e4b8190g-089.jpg?height=88&width=554&top_left_y=373&top_left_x=837)

the information 4 would be correct and the nickel would be in chest 3. Then the third information must be false, and we should have the bronze also in chest 3, which is an impossibility. Therefore, this possibility is ruled out, and the gold must be in chest 5.

![](https://cdn.mathpix.com/cropped/2024_05_01_30c9a294a58a6e4b8190g-089.jpg?height=94&width=568&top_left_y=661&top_left_x=824)

Indeed, with the gold in chest 5, the information 5 is correct, and the platinum is in the chest whose number is one unit higher than the one containing the bronze. By the false statement of chest 3, we have the bronze in chest 3. Therefore, the platinum is in chest 4. Since the second statement is false, the silver is not in chest 1, and can only be in chest 2. Therefore, we have the following solution.

$$
\underbrace{\text { nickel }}_{1}, \underbrace{\text { silver }}_{2}, \underbrace{\text { bronze }}_{3}, \underbrace{\text { platinum }}_{4}, \underbrace{\text { gold }}_{5} .
$$