Light Bulb Puzzle Answer: Brain Teaser

Turn on switch "A" for 4.7 minutes. Turn it off and turn on switch "B". Open the door and touch the lightbulb.

1. if the light is on, it is "B"
2. if the light is off and hot, it is "A"
3. if the light is off and cold, it is "C"

Thanks to Paul Nagai for this.

George Forman, click to reveal email address@hpl.hp.com    Spam robots may prefer to send to gforman4@hpl.hp.com.