1. Keep the first bulb (A, say) switched on for a few minutes. This will warm the bulb.
  2. Switch the first bulb off, switch another one (B, say) on, go outside to the room where bulbs are place by keeping this bulb (B) on.
  3. Where you reach to the bulbs, you’ll find that one bulb is lightened up while two others are switched off. Touch both switched-off bulbs and notice which one of them is warm. Using this method you find, bulb A & bulb B and their corresponding switches.
  4. Remaining one-switch must correspond to third bulb.

Feel free to ask questions, send feedback and even point out mistakes. Great conversations start with just a single word. How to write better comments?
  1. you turn switch number 1 on and leave it on for a few minutes, then turn it off. Then flip # 2 on, and leave 3 off. Exit the room to see the bulbs. The light that is on is switch # 2. The light that is off, but warm, is switch #1. The one that is off and not warm, is #3.

    Good puzzle. It took me a few minutes.

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