Logic Puzzle - Three Switches

AndysDaddy · #1 08-02-2004, 06:05 PM

Ok, how about this one:
A king finds his daughter “carrying on” with a commoner and orders his execution. The Princess begs her father to spare her lover and knight him so that they may marry. The King, having always been a soft touch for his only daughter, agrees to her demands on one condition. He must prove his worthiness by solving a puzzle. The man is taken down into the dungeon and shown a bank of three light switches (hey there are still Kings and Princesses, you know). Then he is shown a prison cell with a single light fixture on a table. The door to the cell is closed and the King says to the Prince-wannabe: “I will open this door again in thirty minutes, at which time you will be immediately escorted into the cell. You will then have one minute to tell me which switch operates the light. If you are right, you will be knighted and may marry my daughter. If not, you will be locked away in the cell to await your execution.

Keep in mind that this is a high tech cell door -When closed, the cell is completely sealed – no light can be seen through the door. Also, once the King opens the door again, the commoner has no opportunity to play with the switches. Finally, it is not a trick question. Exactly one of the switches operates the light in the room.

kyro · #2 08-02-2004, 06:19 PM

Hmm, here's what I'd do...

Turn on the first light switch, keep it on for 20-25 minutes. Turn it off. Turn on the second light switch and keep it on. When the king comes down to escort me into the cell, I'd ask him to join me because frankly, he's more attractive then the butch princess. When he rejects my offer, I look at the light. If it's on, I know it's the second switch. If it's off, but warm, it's the first switch. If it's off, and cool, it's the third switch.

AndysDaddy · #3 08-02-2004, 06:24 PM

Nice work, and exactly correct. But proper protocol is to put your answer in white text so as not to spoil it for others. Like this: Here's my answer [img]/images/graemlins/smile.gif[/img]

kyro · #4 08-02-2004, 06:40 PM

Ahhhh I forgot.

Just for that I will force myself to fold on the river for one bet in a 30BB pot and then tell Ed about it.

jwvdcw · #5 08-02-2004, 06:42 PM

Ah man....I've heard this one before but I can't remember..gimme a while and it'll come to me.

jwvdcw · #6 08-02-2004, 06:44 PM

Ok, I think I got it:

 Turn light switch#1 on for 29 minutes. Then turn it off and turn light swtich#2 on. If the light is on when you go in, its #2. If the light is hot it is #1. If the light is off and cold, its #3.

Lottery Larry · #7 08-02-2004, 08:24 PM

I think the time has to be longer or you risk guessing wrong. 29 is much better

kyro · #8 08-02-2004, 08:58 PM

Well, yeah. Basically, I didn't think you could leave a light on when you went in the room when I was typing out my answer. I was going to say 20 minutes for the first switch, then 10 minutes for the second switch. I guess I was going to measure by hot or super hot?

Anyways, after I convinced myself I could leave a light on, I was too lazy to change it to 29 minutes, but you ARE right.

Lottery Larry · #9 08-03-2004, 09:52 AM

If I had been the commoner and was too stupid not to get caught fooling around with the princess, I doubt I would be smart enough to figure out the answer.

Kurn, son of Mogh · #10 08-03-2004, 10:48 AM

Easy. He immediately flips 2 of the three switches to *on*. When it's time to go in the cell, he flips on of the *on* switches to *off*. He then goes into the cell. If the light is on, it's the *on* switch. If the light is off, he feels the bulb. If it's hot, it's the switch he just flipped to *off*, if it's cold, it's the 3rd switch.