Jump to content
BrainDen.com - Brain Teasers
Sign in to follow this  
rookie1ja

Bulbs

Recommended Posts

Guest

If there are three lamps and three bulbs.. logic would tell me that all three bulbs need replacing so it doesn't matter which goes in which lamp..just walk in and replace them all.

Share this post


Link to post
Share on other sites
Guest

Stop imagining, you can go to the room with the bulbs and then check the switches and the bulbs simultaneously

Share this post


Link to post
Share on other sites
Guest

turn the 1st switch on and leave it on,

keep the 2nd switch off,

turn the 3rd switch on for a minute then turn it back off,

go in room once and feel the two turned off bulbs,

1st switch=bulb is on

2nd switch=bulb is off and cool to the touch (no swearing involved)

3rd switch=the the one you burned your fingers on and most likley swore at the top of your lungs at (unless you remembered to lick your fingers first)

Share this post


Link to post
Share on other sites
Guest

The answer is simple: Flip switch one on, wait two minutes. Turn off that switch, turn on switch two. Walk into the room, the lit bulb is switch two, feel the others, the warm bulb is one, the cold bulb is three.

Share this post


Link to post
Share on other sites
Guest

Its easy. You turn on two of the switches and let them stay on for 2 minutes. Then you turn one off. Go into the room. One of the lights should be on and two off. Carefull touch one of the two bulbs that are not on, the one that is warm goes to the one you turn off before you entered the room.

Bingo

Share this post


Link to post
Share on other sites
Guest

turn on 2 switches for 10 minutes- then turn off on. go in the room- the bulb that's on is the switch you left on. the one thats still warm is the switch you just turned off and the one thats cold is the switch you didnt touch

Share this post


Link to post
Share on other sites
Guest

this is easy.

Leave the first switch without flipping it.

Go to the second switch and leave it on for a little while then flip it off.

go to the third switch and flip it on.

so...

If the light is on it is the third switch

If the light is hot it is the second.

If the light is cold and off, it is the first.

Share this post


Link to post
Share on other sites
Guest

flip two switches on. You will see the lights go on by the light streaming through the door in the adjacent room

Go to the room and remove one of the glowing bulbs from its lamp. PLease use a folded cloth so that you dont burn. Only one bulb is now glowing.

Go back to the switches and return the on switches off one by one.

the switch you flick that turns the room dark is the switch for the on bulb you did not remove.

the other on switch is for the bulb you removed.

the third switch that was left off is for bulb that was of when you entered the room.

Share this post


Link to post
Share on other sites
Guest

Turn on Switch 1, leave on a few mins

Turn off Switch 1

turn on switch 2

Walk into the room

The bulb that is on is for switch 2, the warm bulb is for 1, the cold bulb is for 3.

Share this post


Link to post
Share on other sites
Guest

its easy, i remeber that if a light is one for a minute then turning it off it will dim. first u turn the one on the left on then 30 seconds later u turn the middle one on. then another 30 seconds turn the last one of and at the sam time turn the first one off and 3 seconds later the second then the third at the same time, the one totally black is switch number three, the one that dims second is number two, and the las is number one

Share this post


Link to post
Share on other sites
Guest

Turn on the first switch and leave it on for a while turn it off and then turn on switch two and walk into the room and the light thats on is to switch number two and the warm one is switch one and the other light is to switch three.

Share this post


Link to post
Share on other sites
Guest

All of the switches are attached to only one bulb. To know the bulb to which they are all attached, you only need to turn on one switch.

Share this post


Link to post
Share on other sites
Guest

Put on leftmost switch and wait for 2-3 minutes. After that Put off that switch and put on middle switch and walk in the room. One bulb would have been glowing, this is the bulb pertaining to middle switch. Touch the bulb; if it's hot:leftmost switch; if it's cold:rightmost switch. Thus we trace all switches pertaining to each bulb.

Share this post


Link to post
Share on other sites
Guest

Turn on 1st switch, leave it on.

Turn on 2nd switch for 10 minutes, then turn off.

Leave 3rd switch alone.

When you enter adjacent room, you'd know:

- lit lamp belongs to 1st switch

- lamp with hot bulb belongs to 2nd switch

- lamp with cold bulb belongs to 3rd switch

Share this post


Link to post
Share on other sites
Guest

take battery and release battery into a water wait 4 min or 5 min

and burn water see what happen

take bulb and release bulb in to a water

(it doesn't burn water?)

do not play electric now you may shocked

switch on plug and release plug into water

don try this at home!

don do it

Share this post


Link to post
Share on other sites
Guest

Leave one switch off= bulb off

Turn one switch on for about 10 to 15 minutes (long enough to get hot), then turn on last switch and walk into room with bulbs

feel which one is hotter to detemine which switch goes to which bulb

Share this post


Link to post
Share on other sites
Guest

It truly is amazing that people will still continue to post the same solution, over and over, for 20 pages.

Share this post


Link to post
Share on other sites
Guest wlyeung
Bulbs - Back to the Logic Puzzles

This is one of my favorite logic puzzles (Edit: it is more a practical than a logic puzzle).

Imagine you are in a room with 3 switches. In an adjacent room there are 3 bulbs (Edit: let's say in lamps which are on a regular table) - all are off at the moment, each switch belongs to one bulb. It is impossible to see from one room to another. How can you find out which switch belongs to which bulb, if you may enter the room with the bulbs only once?

Edit: No help from anybody else is allowed.

Edit: Find out which switch belongs to which bulb - identify all 3 switches (so find out what bulbs are switches 1, 2 and 3 connected to)

Bulbs - solution

Keep the first bulb switched on for a few minutes. It gets warm, right? So all you have to do then is ... switch it off, switch another one on, walk into the room with bulbs, touch them and tell which one was switched on as the first one (the warm one) and the others can be easily identified ...

I got the solution exactly! in 2 minutes

Share this post


Link to post
Share on other sites
Guest 4811922

or you could turn one bulb on, wait long enough for it to burn out, turn another on, and check.

Share this post


Link to post
Share on other sites
Guest

Answer: Turn on two of the switches for a period of a few minutes, then turn one of them off. (of course this solution assumes the lights begin in the "off" position.)

Go into the next room, the bulb that is off, but warm belongs to the switch that was on, but is now off, the bulb that is on, belongs to the switch that is in the on position, the bulb that is off belongs to the final switch.

Nice puzzle.

B)

Share this post


Link to post
Share on other sites
Guest

personally, i would first turn on one lightswitch and leave it on for a good ten minutes. then i would turn on a second lightswitch and immediately go to the adjoining room where obviously the light that was off belonged to the lightswitch that i left off, and then the other two lights , one would be hot from being on which would be the first lightswitch and the light bulb that i could probably touch if i entered right away would be the switch that i had turned on second

then its solved

Share this post


Link to post
Share on other sites
Guest

You could do the "feel which bulb is warm" suggestion that people have posted.

However, that might not work.

What if it turns out that the bulbs are flourescent? They do not generate much heat at all. You might not be able to feel a difference. If you don't believe or know this, turn on a flourescent bulb for an hour and then touch it. It will not be hot or even warm at all.

This is how I see doing this.

- label (at least mentally) the three switches A, B and C.

Now the bulb that is controlled by each switch receives the same letter.

So, switch A controls bulb A, etc.

- Now, we have to figure out which bulb is bulb A, which bulb is bulb B, and which is bulb C.

- turn on switch A and leave it on.

- wait until the light bulb burns out.

(OK. That would be a long time. But theoretically, we can wait as long as we want.)

You can tell when the one lit bulb burned out because the other two are still off.

You can see that no light is coming from the other room as soon as the one bulb burns out.

- After the one bulb burns out, turn the other two switches (B and C) on.

Now, all three switches are on.

But, only two bulbs are lit because the third is burned out.

- Enter the room.

Whichever bulb is off (i.e. burned out) is bulb A and controlled by switch A.

Now we just have to figure out which of the other two bulbs is bulb B and which is bulb C.

- Remove or break one of the lit bulbs.

Now there is only one lit bulb and one burned out bulb remaining.

The bulb we broke is either B or C. But, we don't know which one... yet.

The bulb that is still lit is either B or C. But, we don't know which one... yet.

And bulb A is still the one that we observed was Off (burned out) when we entered the room.

- Leave the room and return to the switches.

Remember, all 3 switches are "ON". But, only one bulb is lit. It is either bulb B or C.

- Turn off switch A because you already know that bulb A is burned out.

You now have switch A Off, switch B on, and switch C On.

And there is still light coming from the other room.

The light is coming from either bulb B or C.

- Now turn off switch B.

You now have switch A Off, switch B Off, and switch C On.

If the light coming from the room is now gone, then you now know that the bulb that was lit when you left the room is bulb B. And you now know that the bulb that you removed (or broke) was bulb C.

If the light in the room is still on, then you now know that the bulb that was lit when you left the room is bulb C. And you now know that the bulb that you removed (or broke) was bulb B.

Edited by KnightTrain

Share this post


Link to post
Share on other sites
Guest

turn on one light switch, wait a half hour and then turn it off. Turn on another switch, and with it still on walk into the other room. Which ever lamp is on that is the switch that is on. Whichever light bulb is hot is the lamp that belongs to the first switch that you turned on. the lamp that is neither on nor hot belongs to the switch you never turned on

Share this post


Link to post
Share on other sites
Guest
This topic is now closed to further replies.
Sign in to follow this  

  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...