December 14th, 2006 @ 7:21 pm
light bulb
Light Bulb riddle: There are three on/off switches outside of a room, only one controls an out-of-sight light bulbs in the room. You may manipulate the switches (only to the extent of turning them on and off), then you must go into the room with the light bulb and stay there until you have determined which switch it is connected to. How do you do it?
we did some brainstorming in class and there were a couple different riddles
can you solve it without cheating? how long can you read the question before you decide to look for the answer?
5 Responses to “light bulb”
Am I missing something? Let’s label the switches A, B, and C. Starting with all the switches in the down position, can’t you turn A on, go check if the light is on, if it’s not, go back to the switches, turn A off, then turn B on, go check, and repeat? If you want to make less trips, turn two light switches on at the same time, check in the room, if the light’s not on, it is the switch that you did not activate. If the light is on, turn one of the switches off, check again. Is a piece of the puzzle missing, or is it really that simple?
By Brian December 15th, 2006 at 3:03 pm
you must go into the room with the light bulb and stay there until you have determined which switch it is connected to.
once you enter the room you cannot leave until you know the answer.
By justin December 15th, 2006 at 4:46 pm
“only one controls an out-of-sight light bulbs in the room.” meaning, the other 2 switches control lights that are visible?
or,
can you reach the light switches from inside the room?
By zrn December 16th, 2006 at 10:58 pm
no
By justin December 17th, 2006 at 12:09 pm
Going with the A,B,C labels. Turn A and B on, wait a little while then turn B off. Then go into the room. If the lightbulb is then on it’s A, if the lightbulb is off but hot then it’s B, if the lightbulb is off and cold then it’s C.
By Will December 23rd, 2006 at 7:59 am