# A Logical Puzzle

Discussion in 'Off-Topic' started by BoyntonStu, Apr 21, 2009.

1. ### BoyntonStu Thread Starter Active Member

Apr 18, 2009
52
0
There are 3 lamps in a sealed room, each lamp is on a table, they are A,B,C

There are 3 SPST wall switches on the wall outside the room, and each switch controls a single lamp inside the room. They are 1,2,3.

You can not see the effect of turning on any switch when you are outside the room.

You can manipulate the switches in any way.

After you are done with the switches, you may enter the room once and close the door behind you.

How can you determine which switch controls lamp A, B, and C?

BoyntonStu

2. ### vvkannan Active Member

Aug 9, 2008
138
11
Switch ON 1 for some time and it will get heated.Now press switch 2 and enter the room.The glowing BULB corresponds to 2,heated one to 1

3. ### Dave Retired Moderator

Nov 17, 2003
6,960
170
The family had some fun with this puzzle at Christmas. It's a good one.

Dave

4. ### thingmaker3 Retired Moderator

May 16, 2005
5,072
8
This puzzle works best with incandescent bulbs, and more poorly with LED bulbs.

5. ### m4yh3m AAC Fanatic!

Apr 28, 2004
186
43
I look at the schematics to the room and see how the wiring is laid out. Then I question the sanity of someone who builds a room only to seal it off and make logical questions of it.

6. ### thingmaker3 Retired Moderator

May 16, 2005
5,072
8
The room was part of President Obama's economic recovery plan.