Puzzle: Two Rooms, Three Switches and Three Light Bulbs…
March 6th, 2006
Ok, I’ll try to write this puzzle as clear as possible…
There are two rooms. One room has a table with three light switches on it. The other room has a table with three light bulbs connected to light fixtures. If you turn on all three switches in one room, all three light bulbs will turn on. If you turn off all three switches, all three lights bulbs will turn off.
The puzzle is this…
You have one turn to set the light switches, and then go to the other room and tell which switch goes to which light. Meaning, you set the switches and go to the other room and give the answer. You can’t go back and forth. You only have one shot. You cannot see one room from the other.
How do you do it?
(If you want me to clarify the question, leave a comment)
Flip two switches on. After about 2 minutes turn one off and go to the other room. One bulb will be burning, another will be turned off but still warm, the third will be off and cool to the touch.
Someone gave me this quandry a few days ago. My solution was as follows… Turn on switch 1 and 2. Wait a few minutes. Turn off switch 2. Go to the second room.
Lit bulb = Switch 1
Dark warm bulb = Switch 2
Dark cool bulb = Switch 3
I’m confident that my solution holds water, but I’m curious if it is the traditional solution.
That is the traditional solution!
I was asked this question during a job interview (along with 3 others) and it took me 20 minutes to get this answer…
Turn one on, leave it on for ten minutes or so. Turn another on and go to the other room.
Hot light on = first switch turned on…
Warm light on = second switch…
light off = third switch..
The interviewer said he accepted my answer as correct but he said physics wasn’t my strong suit because it may have been hard to tell which light was turned on first depending on the heating coeffitiant(sp?) of glass…
So I say I got it half right.
the reason you are both wrong is because what if the bulbs are far away.
HERE IS THE REAL SOLUTION with no “this one might be warmer than the other”
label switches 1,2,3
turn switch 1 on for 5 min turn off
leave swith 2 off
turn 3 on
the only warm one is switch 1
the one that is cold is 2
and the one that is on is 3