Logic Problem : Three switches | Sololearn: Learn to code for FREE!
+ 6

Logic Problem : Three switches

You have just entered a darkened building. It is early evening. In front of you is a staircase to the next floor. Next to you are three switches. One (and only 1) of these switches controls a working light bulb. The bulb is on the next floor. You cannot see the light from here (assume a perfectly-blocking door). You may flip the switches as you please. Then, you are allowed only one (1) journey to check the light (no more switch flipping). After checking: Which switch controls the light?

6th Apr 2017, 9:04 PM
Kirk Schafer
Kirk Schafer - avatar
12 Answers
+ 17
Taking from @Micheal, Say I turn on switch 1. I leave it on for 10 minutes. After 10 minutes, I turn on switch 2 and immediately go on the journey to check the light. If the light bulb is switched on, the switch would be 2. If the light bulb is off, but it is warm, the switch would be 1. If the light bulb is neither on nor warm, the switch would be 3. ... Then again, Idk if I'm tall enough to reach the light bulb. 😐
7th Apr 2017, 12:32 AM
Hatsy Rei
Hatsy Rei - avatar
+ 15
Is it something to do with lightbulbs getting hot?
6th Apr 2017, 9:50 PM
Michael Foster
Michael Foster - avatar
+ 14
Ooh, I know this one! (That is, if I can tell you the answer after going upstairs) 👍
6th Apr 2017, 9:08 PM
Jafca - avatar
+ 12
@Hatsy Rei Good answer
7th Apr 2017, 12:34 AM
Agus Mei
Agus Mei - avatar
+ 7
The default switch? 😛
6th Apr 2017, 9:41 PM
Rrestoring faith
Rrestoring faith - avatar
+ 6
Marked @Hatsy Rei as best. I'll look at Michael's/etc. codes for some upvotables, because: timing & I used such questions to clarify. I like this problem because it requires some thinking in meta-information, but I wasn't positive I could allude to that without giving it away.
7th Apr 2017, 12:49 AM
Kirk Schafer
Kirk Schafer - avatar
+ 5
@Jafca, yes :) Edited to clarify I hope.
6th Apr 2017, 9:10 PM
Kirk Schafer
Kirk Schafer - avatar
+ 5
@Michael Foster : Does it prove anything?
6th Apr 2017, 10:17 PM
Kirk Schafer
Kirk Schafer - avatar
+ 5
@Rrestoring faith: Do you mean the one often on the light itself? That's a funny little loophole; just not the one I'm looking for :)
6th Apr 2017, 10:23 PM
Kirk Schafer
Kirk Schafer - avatar
+ 5
journey upstairs and start throwing thongs at the light bulb. once the light bulb is broken the answer is easy. none of them control the light bulb as it is broken
7th Apr 2017, 12:47 AM
david schlemmer
david schlemmer - avatar
+ 5
@david schlemmer - haha, it sounds like you have the answer to this one, too: https://www.sololearn.com/discuss/299535/?ref=app
7th Apr 2017, 12:52 AM
Kirk Schafer
Kirk Schafer - avatar
+ 4
haha ive heard this one before.
6th Apr 2017, 9:09 PM