You're in a room with three light switches labeled A, B, and C. Each switch controls one of three light bulbs in another room that you can't see from your current location. You're allowed to enter the other room only once, after which you must correctly identify which switch controls each bulb. How can you determine which switch controls each light bulb?
Here's the reasoning behind solving this puzzle:

1. First, turn on Switch A and wait for a few minutes.
2. After waiting, turn off Switch A and turn on Switch B.
3. Now, enter the other room with the light bulbs.
4. The bulb that is currently lit is controlled by Switch B (since it's the only switch that's turned on).
5. The bulb that is off but warm to touch is controlled by Switch A (since it was on long enough to heat up the bulb before being turned off).
6. Finally, the bulb that is off and cool to touch is controlled by Switch C (since it was never turned on).

So, by following these steps, you can accurately determine which switch controls each light bulb without entering the other room more than once.