#1:

You are standing in a hallway. in that hallway there is a door and 3 light switches all identical to eachother
inside the door is a room with a single light bulb hanging from the ceiling
you have to determine which switch in the hallway operates the light in the room
rules:
you can only go into the room once
the door must remain shut until you use your one chance to go in the room
you cannot see around the door frame (it is well sealed allowing no light to be visible)
you have all the time you want

which switch operates the light???


#2

there are four people on one side of a bridge
one person can get across the bridge in 1 minute
another person can get across in 2 minutes
another takes 7 minutes
and the last person takes 10 minutes to get across

they can only cross if they have a flashlight
they only have one flashlight
they can only cross 1 or 2 at a time
they can only go as fast as the slowest person
they must cross, bring the flashlight back to get someone else across, and so on
they only have 17 minutes to get all 4 people across the bridge

in what order must they cross the bridge???

#1
Turn on switch 1 for 2 minutes. Turn off switch 1.
Turn on switch 2 for 30 seconds. Turn off switch 2.
Enter the room and feel the light bulb. If it is hot, switch 1. If it if just warm, switch 2. If it is cold, switch 3.

#2
Still working on the bridge one......tricky! :confused:

#1

I think that I would have done it slightly different. Turn #1 on for 2 minutes turn off #1 and turn on #2 and leave it on and walk into the room. If the bulb is off and warm then #1 if the light is on then #2 else #3.


#2

1&2 cross = 2 Minutes
1 goes back = 3 minutes
5&10 cross = 13 minutes
2 goes back = 15 minutes
1&2 cross = 17 minutes

Paul seems to have aced #2 with a typo (7 not 5) ;) but I'm not sure about either answer for #1 even though they both would work.

In #1 nobody said you couldn't open the door and try the 3 different switches. It just says the door has to remain shut until you decide to go into the room. :D

Aww....it was just a problem with the interface between the chair and the keyboard..... :D

Good job guys. Actually your supposed to walk in the door when it opens, so only one shot. The heat trick is the right one.