Riddle: 5 lights

This is an update to the post: http://fulldecent.blogspot.com/2009/01/profile-riddle-is-back-lights.html

----

The riddle has so far received no correct answers (several people responded with the obvious "cop out" answer). Therefore, this is being declared the hardest riddle yet. I am upgrading the bounty to 2 points for a correct answer! Also, I am making the riddle a little harder...


You are outside a room with 5 light switches. You cannot see in the room. You don't have anyone else to help you. You enter the room. Inside the room are 5 lights. You then find out which light switch controls which light.


This is very difficult. So remember, you are encouraged to Google around for similar riddles and to ask your friends. Cheating is encouraged!

SEND ME YOUR ANSWERS!!

UPDATE: The answer is posted at: http://fulldecent.blogspot.com/2009/02/5-lights-riddle-answer.html

Comments

Tyler McHenry said…
I'm not sure if this counts as a cop-out answer (and this obviously wouldn't work with CFL bulbs, but then again neither would the 4-bulb solution) but:

Chose 1 switch. Flick it on and off continuously for a good, long while (say, a few days), or alternatively leave it on for a very long time (like, a year or two). The point is that the problem specifies no time limit.

Once you've done that, then with the remaining four switches do the same thing as with the four-switch problem. Turn two switches on for a few minutes, then turn one of them off and turn another on. Quickly enter the room and feel the bulbs.

You should be able to differentiate the last four bulbs between on/hot, on/cold, off/hot, off/cold as with the four-switch problem. The fifth bulb, the one with the broken filament, is the first one you chose.
4:42 PM
William Entriken said…
Thank you for your submission. I saw a another solution like from Duncan this and considered whether the underlying assumption is valid: after turning on, a bulb does not get hot immediately.

Previously I thought this assumption fails and even tested it. However, now I see that for lower watt bulbs it is true! Naturally, valid assumptions are given to contestants, and Duncan retroactively gets his point.

You, sir, are however WAY past the deadline.

FYI the cop out answer was: the switches are labeled.
7:51 PM
Post a Comment

Popular posts from this blog

Nontechnical: What is ERC-721?

Image
Read time: 6 minutes. This post explains how ERC-721 works and does not require any prior knowledge of Ethereum or blockchain. 简体中文 -->  http://www.sfgroup.hk/news_post/通俗易懂的告诉你什么是erc-721/  （奇点财经翻译） How does your phone connect to a web server? Most of your time on computers/phones/technology is spent with a web browser accessing a web page. Most of the screens you see out in the world that display information are usually using a web page to show it, but they just hide the URL bar. The flight arrivals screen -- it's just a web page Think for a minute about how this ubiquitous technology works. You.  You are very busy and you are trying to access some information, maybe cat videos or sports scores or your family members' feedback on a photo you posted of your kid.  Your phone , or whatever other device is in your hand, that acts on your behalf. The web server decides how it wants to reply to your request. Technology people, the ones that ma...
Read more

I Was Kidnapped in Manila and Lived to Tell About it

Image
Other potential titles: The US Embassy Doesn't Want You Know About This Kidnapping in Manila Scopolamine / Devil's Breath Trip Report It started Easter weekend This story starts at Noon Tuesday April 18th, 2017 on Makati Avenue. I just finished a meeting with the Philippines Board of Investments to discuss how my company can expand our business in Manila. (Also saw the QBO Innovation Hub , it was awesome.) I had plenty of time to kill and some emails to catch up on, so it's time for some brain food! I walked right to the hottest part of town, Makati Ave. and Jupiter Ave. , surely there will be something good to eat. And then suddenly, The Guy approaches me, I'm marked. Hey, I know you are you staying at the Jazz Residences? Jazz is about a 12 minute walk to here, and I did not walk towards Makati Ave. from that direction since I just came from the meeting. I'm always guarded with information and paying attention to stuff like that. There's abo...
Read more

The best number on Google Voice

Image
I got a GV invite today and had to choose which number I want. Of course all the repeated digits are gone (215-777-7772, ...) are gone. Google provides a simple interface to find a good number, but this is the interface I like, grep: ===So I did the following (Mac 10.5 / Safari)=== 1. Download all available Google Voice phone numbers  for a given area code. 2. Normalize the data: grep -ho +1484....... *js | sort -u | cut -c 3- > numbers 3. Grep through to find the best numbers available (some example results shown): # repetition grep "\([0-9]\{4\}\).*\1" numbers >> 4843248432 #pairs grep "\([0-9]\)\1.*\([0-9]\)\2.*\([0-9]\)\3" numbers >> 4842220022 >> 4842220044 # repetition grep '\([0-9]\)\1\{3\}' numbers >> 4849388886 # only 3 digits (mostly) grep '^[483]\+.$' numbers >> 4843344881 # palindromes grep "\([0-9]\)\([0-9]\)\([0-9]\)\([0-9]\).?\4\3\2\1"...
Read more