BrainDen.com - Brain Teasers

Bulbs

Recommended Posts

you turn one on for ten minutes let it get warm then turn it off

turn the second one on

and dont touch the third one

now the first switch is the bulb that is off but warm

second one is on

third one is off and cold

• Replies 257
• Created

Popular Days

Why are so many people repeating the correct answer?

How many lives have LED room lights penetrated?

Share on other sites

My solution was a little different, but quite similar I guess.

Turn on two switches, walk into the lightbulb room, the 'off' light is with the 'off' switch. Unscrew one of the two lightbulbs so it is no longer lit, go back to the switches and flip one of the 'on' switches to 'off', see if the light goes out in the other room or not and you've identified your 3 switches.

It would require being able to see light coming through the door from the other room - although it would work with LED bulbs.

Share on other sites

ON 1 Switch (Let it be for a minute or so)

Now Switch it OFF

Swicth ON 2 Switch

Go to the room where the bulbs are there.

The bulb that is not glowing and cool is for Switch 3

The bulb that is not glowing and warm is for Switch 1

The bulb that is glowing is for Switch 2

Share on other sites

Turn on two switches

Wait a minute and turn one off.

Go to the other room. One light is on-the switch that you left on. One light is off but warm-the switch you switched off. One light is off-the switch you didn't touch

Share on other sites

first on the switch for some time................

and off the first switch and on the second one

now go to the next room

the bulb which is on is the second switch

touch the other two bulbs...

then the bulb which is cool,is of third switch

and the other bulb which is somewhat hot is of first switch..

Share on other sites

Make a map of the switches.

Keep one switch off - label as "A"

Turn the second switch ("B") on for a few seconds, then turn off.

Turn and keep the third switch ("C") on.

Go to the next room.

The bulb that is off and cold belongs to switch A

The bulb that is off but warm belongs to switch B.

The bulb that is on belongs to switch C.

Share on other sites

i believe i figured it out. here is my solution.... You turn on one switch, leave it on for a few minutes, then turn it off. Immediately turn on one of the other switches and walk into the room. Now feel of the two bulbs that are not lit up and the one that is warm to the touch is the first switch you turned on and the one that is not warm is the last switch that was not turned on!

Share on other sites

I'm seriously curious why this puzzle, which has the solution included in the first post, compels so many people to create an account just to post their re-worded solution based on the same concept that a light can be on, off and cold or, off and hot.

Any ideas?

Share on other sites

How can you tell it if it is now brownout?

Share on other sites

If we assume there is a doorway through which you can visually see the lights turn on and off, you can turn a switch on and then enter the room. You see which light is on and then remove an unlit bulb walk out, turn off the first switch and then turn on another switch. If the room lights up then you turned on the switch with the bulb still attached. If it doesn't you identified it as the one where the bulb was removed. No burnt fingers.

Share on other sites

There is no restriction that says you cannot seek the help of a friend or even any other human nearby. Thus you simply have someone stand in one room and note which switch they flick (maybe left to right or something) while in the bulb room you note which bulbs light up (or vice versa).

Share on other sites

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.

There is no restriction that says you cannot seek the help of a friend or even any other human nearby. Thus you simply have someone stand in one room and note which switch they flick (maybe left to right or something) while in the bulb room you note which bulbs light up (or vice versa).

Yeah there is a restriction since this would make the situation a chore not a puzzle.

Share on other sites

Bulbs

This is one of my favorite logic puzzles.

Imagine you are in a room with 3 switches. In an adjacent room there are 3 bulbs (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?

My solutionm to this come from reading the language very carefully. ...In an adjacent room there are 3 bulbs (all are off at the moment)

suggesting that the bulbs are not in their socket...

So i would flick ON only two of the three switches and walk into the other room where the bulbs are and insert two bulbs into their socket (may have to try several sockets). Once those two are lighted...i will know that the switch in the other room that was LEFT on OFF is for the 3rd bulb that is not lighted in the remainig socket..

Megs

Share on other sites

Bulbs

This is one of my favorite logic puzzles.

Imagine you are in a room with 3 switches. In an adjacent room there are 3 bulbs (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?

My solutionm to this come from reading the language very carefully. ...In an adjacent room there are 3 bulbs (all are off at the moment)

suggesting that the bulbs are not in their socket...

So i would flick ON only two of the three switches and walk into the other room where the bulbs are and insert two bulbs into their socket (may have to try several sockets). Once those two are lighted...i will know that the switch in the other room that was LEFT on OFF is for the 3rd bulb that is not lighted in the remainig socket..

Megs

If you read it more carefully, it says "each switch belongs to one bulb" meaning you should not have to assign the bulb to a socket yourself thus saving you the round trip if you use the correct solution.

Share on other sites

thats easy turn on 2 swithches wait awhile turn off 1

then go into the room and feel the lightblubs and you

you will know which switch goes with which lightblub!!

Share on other sites

I agree with mdsl

I'm seriously curious why this puzzle, which has the solution included in the first post, compels so many people to create an account just to post their re-worded solution based on the same concept that a light can be on, off and cold or, off and hot.

Any ideas?

Its not only with this topic. its all over this forum. what are the chances that people who are posting Re-worded solutions havent read the solution?

for example i try not to post any solutions, unless i'have a different way of solving it...

anywayz keep up the good work people.... peace...

Share on other sites

I strongly agree to the person who said that by turning on one switch you would certainly know which bulb it belongs. Simple right.

Share on other sites

omg. u people. this is a clasic riddle! you turn on one light switch and leave it on. you turn on the 2nd light switch and then turn it off 5 mins later. you leave the 3rd switch off. then you go into the other room. the light bulb that is on goes with the light switch that you turned on and left on. the light bulb that is off, but hot goes with the light switch that you turned on then turned off again. and the light bulb that is off and cold goes with the switch that was never turned on.

Share on other sites

that's great one, thanks =)

Share on other sites

Take the wall switch plates apart and hook 3 different batteries, with different voltages, to each. Then enter the room and either visually look at the different brightnesses of each bulb or unscrew them from thier sockets and measure the output with a voltmeter.

So, simple.

Share on other sites

I'm sure someone else has already answered this with all the messages that have been posted, but I will post my solution anyway: Turn on the first switch, leave it on for a while, then turn it off. Then turn on the second switch and walk into the room. The warm lightbulb that is off connects to the first switch. The lightbulb that is on connects to the second switch, The room temperature bulb that is off connects to the third switch.

Share on other sites

Assuming regular doors are not completely flushed with the frames an some light can come from the sides or from the bottom, the solution is to turn on switch #1, get into the room to find out which bulb it's connected to, remove one of the off bulbs, go back to the switches, turn off #1 and test the other switches to find out which one lights the room and gives us some light around/under the door.

Share on other sites

The solution I come up with is to turn two switches on and leave one off. Go into the room and see which two are on. The one that is off lets you know which one is connected to the switch you left off. Take the bulb out of the socket of one which is on. Go back to the room and turn off one of the switches. If the light goes out you know that that switch is connected to the one that still has a bulb in it. If the light doesn't go out then that switch is connected to the one with the empty socket. This leaves the last switch obvious. So logical...

Share on other sites

lol ur joke is .....

GR8 NOT!!!!

Share on other sites

This topic is now closed to further replies.