Hard
Brain Teasers for Adults
11 XP

The Light Switch Puzzle

16,992 solved 70% solve rate 30% fail rate
You are outside a room with 3 light switches. Inside are 3 bulbs. You can only enter the room once. How do you determine which switch controls which bulb?
Only 70% solve this correctly
16,992 attempts
Earn +11 XP for solving
Quick Answer & Explanation
Turn switch 1 ON

The answer to this riddle is Turn switch 1 ON. Difficulty: Hard ยท Solved by 16,992 puzzle lovers.

Turn switch 1 ON for 10 minutes, then OFF. Turn switch 2 ON. Enter. The warm bulb is switch 1, the ON bulb is switch 2, the cold OFF bulb is switch 3.
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