# Light riddle

Raindear
Posers and Puzzles 27 Jan '06 18:36
1. 27 Jan '06 18:36
This is not original, but I thought it was pretty clever...

You go into a house and there are three light switches on the first floor operating three lights on the second floor. You must figure out which switch corresponds to which light, but you can only go upstairs once. How do you do it?
2. 27 Jan '06 18:39
Originally posted by Raindear
This is not original, but I thought it was pretty clever...

You go into a house and there are three light switches on the first floor operating three lights on the second floor. You must figure out which switch corresponds to which light, but you can only go upstairs once. How do you do it?
ok. you flip two switches, wait a few minutes, and turn one off. Go upstairs. If the lightbulb is on, it is the switch you left on. If it is warm, it is the switch you turned off. If it is cold, it is the switch you did not flip.
3. 27 Jan '06 18:41
Right, you are. (: That was quick.
4. 27 Jan '06 20:10
Originally posted by Raindear
Right, you are. (: That was quick.
it was easy...
5. sonhouse
Fast and Curious
27 Jan '06 20:141 edit
Originally posted by ketch90
it was easy...
Ah, you didn't know they were flourescent lights? No heat.
However, if you were fast enough, you could rush upstairs and see
what light beams are closest to the lights....
6. 08 Feb '06 02:49
Originally posted by sonhouse
Ah, you didn't know they were flourescent lights? No heat.
However, if you were fast enough, you could rush upstairs and see
what light beams are closest to the lights....
a light beam obviously moves at the speed of light so how would you move up stairs fast enough to see the ?
7. 08 Feb '06 05:04
Originally posted by Raindear
This is not original, but I thought it was pretty clever...

You go into a house and there are three light switches on the first floor operating three lights on the second floor. You must figure out which switch corresponds to which light, but you can only go upstairs once. How do you do it?
You go up to the room and set up a sequence of mirrors down to where you stand.
8. TheMaster37
Kupikupopo!
08 Feb '06 08:36
Originally posted by Coconut
You go up to the room and set up a sequence of mirrors down to where you stand.
Or tie strings to the switches.
9. sonhouse
Fast and Curious
09 Feb '06 00:16
Originally posted by sofar55
a light beam obviously moves at the speed of light so how would you move up stairs fast enough to see the ?
Well I said, IF you were fast enough. Remember, the light is
coming towards you so maybe you could distinguish which beam
is in front.
10. 10 Feb '06 04:20
Ooorrrr, you could use the phone beside you to call superman....I mean...yes, feel the lightbulbs...
11. 12 Feb '06 11:17
You could set up CCTV upstairs then go back down and watch what happens.
12. Kirwan
Mel Kirwan
18 Feb '06 08:23
I heard a puzzle the other day. No trickery - just mental maths. No paper or pencil allowed.

If a man and a half dig a hole and a half in a day and a half how many holes does one man dig in a week
13. 18 Feb '06 09:43
since you can have half holes in this one i'd say the answer is 14/3 holes. oh and since it's a third of a hole and not half a hole, maybe its alright for the other thread too ðŸ™‚
14. 28 Feb '06 20:40
Originally posted by crazyblue
since you can have half holes in this one i'd say the answer is 14/3 holes. oh and since it's a third of a hole and not half a hole, maybe its alright for the other thread too ðŸ™‚
you can't have half a person nor "half" of a hole because that "half" is still considered a hole...
15. 01 Mar '06 23:10
Originally posted by Kirwan
I heard a puzzle the other day. No trickery - just mental maths. No paper or pencil allowed.

If a man and a half dig a hole and a half in a day and a half how many holes does one man dig in a week
That would be 4 and two thirds holes.
(Two thirds of a hole!!!!!! Half a man!!!!!!?)
Neil.