Puzzle

Neil · Post by **Neil** » Wed Apr 09, 2003 11:37 am

There is a room complete darkness inside , no windows, flat roof and sealed door. Inside are 3 lightbulbs, all work. Outside are 3 separate switches. Without the use of tools and only by your self (nobody else is present) determine which switch works which bulb. The problem is you can only go into the room once, the door must be opened when you enter and closed behind you, any combination of the switches in on off positions can be set before going into the room. you cannot leave the door open at any time. How do you know which bulb works with which switch.

Can be done, there is not a stupid answer

See if you can work it out.

Post by **Keith Jordan** » Wed Apr 09, 2003 12:58 pm

Switch one light on and then pull real hard on the wire of another one so that it rips the wire out the light and it falls helplessly on the floor. You then know that the light that is not on but still in tact is the third one, the one that is on is the first and the second one is in a state of disrepair.

Just a bit of lateral thinking.

Neil · Post by **Neil** » Wed Apr 09, 2003 1:07 pm

No - but I like your guess

The answer doesn't include sabotage though!

Post by **Keith Jordan** » Wed Apr 09, 2003 1:22 pm

Mark the wires up 1, 2 and 3 then rip them out back to the switches and then you will know?!?!

Neil · Post by **Neil** » Wed Apr 09, 2003 1:33 pm

No it's got nothing to do with the wires. Besides that's sabotage again

Post by **Keith Jordan** » Wed Apr 09, 2003 1:37 pm

Well, I am lost for a logical solution! 3 unknowns and only 1 parameter to work with. So I am thinking it is a lateral thinking problem or am I off the trail?

Neil · Post by **Neil** » Wed Apr 09, 2003 1:41 pm

No it's not lateral - more logical..

Trust me there is a way which will make you kick yourself when you know it! Try thinking more about the lightbulbs themselves..

Post by **Keith Jordan** » Wed Apr 09, 2003 1:54 pm

Lets look at evidence. When switching the light on, it shines and you can see that switch operates that light.

Problem. We can do this to find one light. one parameter for 3 unknowns. No solution.

We need a way of bringing more information into the problem and must focus on the light bulbs for evidence.... weh hey!!! I go it. This evidence we need is information for which switch goes to which light but the light does not have to be on to know it has been on!!!

If we turn on light switch one for 10 mins so that the bulb heats up then we can turn it off. New information to solve the problem. Then we turn on switch 2.

We then go into the room.

Light 1 - is warm
Light 2 - if on
Light 3 - is off and cold

Weh hey!!

grateful pink · Post by **grateful pink** » Wed Apr 09, 2003 1:57 pm

i ususally cannot do these sorts of thing. I started one post, deleted it after thinking of Keith's idea. I think it is correct. I am surprised (if it is correct) that I got this as I may be one of the least logical thinkers alive@

Neil · Post by **Neil** » Wed Apr 09, 2003 2:01 pm

Congrats Keith

Took me a lot longer than that! It had the folks in my office puzzled for 2 days! We're not very bright in Birmingham you know

Post by **Keith Jordan** » Wed Apr 09, 2003 2:06 pm

Logical problems are easy!! Just look at the situation and information you have. Then look at the constraints. In this case, it was the constraint of information itself. Think of how to bring more information or parameters to the poroblem and then you can simultaniously solve the "equation". All good fun.

Alternatively, you can think lateraly and have fun. My favourite one of those is how the scuba diver ended up dead in the middle of the farmers field!! How did he end up there?

Neil · Post by **Neil** » Wed Apr 09, 2003 2:10 pm

Did he die whilst scuba diving in a lake or something, then there was a drought and all the water dried up leaving him in the middle of a field?

Post by **Keith Jordan** » Wed Apr 09, 2003 2:15 pm

Not Now Neil wrote:Did he die whilst scuba diving in a lake or something, then there was a drought and all the water dried up leaving him in the middle of a field?

He was scuba diving in the sea and he did not die during this activity. The field he was found in was always a field and was not a fried up lake. Think lateraly.

grateful pink · Post by **grateful pink** » Wed Apr 09, 2003 2:16 pm

They picked him up in one of those giant water scoops that scoop ocean water and then bring it to a forest fire and let it drop. The scuba diver drops in there with the water.

Post by **Keith Jordan** » Wed Apr 09, 2003 2:18 pm

correct Grateful pink!!