Problem 3

[Symmetry]

There are three switches down­­stairs, each controlling one of the three lightbulbs in the attic. Those bulbs, and their light, cannot be seen without going upstairs, and you're alone. You can turn the switches on and off and leave them in any position, but you are only allowed one trip upstairs. How would you identify which switch controls which light bulb?

As always, the answer is available online if you get stuck.

[TA1LGUNN3R]

Tie a differently colored string to each switch with each switch in the off position (down), with enough length to go upstairs. Go upstairs, pull each string in sequence while observing the bulbs.

-TG

[Army of GOD]

turn one on for a while, turn it off, turn on a second one, go upstairs

the hot off one is the first switch, the one that's on is the second switch, the cold off one is the third switch

unless you're using CFL bulbs

[patches70]

turn one on for a while, turn it off, turn on a second one, go upstairs

the hot off one is the first switch, the one that's on is the second switch, the cold off one is the third switch

That's the answer. Except you turn on both A and B leave C off. Wait five minutes, turn off B and go upstairs. The light that is on is A, the light that is off and warm is B and the light that is off and cold is C.

[Army of GOD]

how is that any different practically to what I said?

[Symmetry]

Either works. I did like TG's string answer though. It's more interesting when people figure out their own solutions.

[TA1LGUNN3R]

Either works. I did like TG's string answer though. It's more interesting when people figure out their own solutions.

Theseus would be proud.

-TG

[Army of GOD]

TG's answer is dumb. what if you're on house arrest and can't buy long string?

[Symmetry]

Either works. I did like TG's string answer though. It's more interesting when people figure out their own solutions.

Theseus would be proud.

-TG

Ariadne was the brains behind that particular operation. Theseus was just the muscle.

[TA1LGUNN3R]

You're dumb if you don't have a couple rolls of string in case you need it. =P

What if your bulbs were cfl or led? Who's dumb now?

-TG

[Symmetry]

TG's answer is dumb. what if you're on house arrest and can't buy long string?

Amazon, moron.

[TA1LGUNN3R]

Either works. I did like TG's string answer though. It's more interesting when people figure out their own solutions.

Theseus would be proud.

-TG

Ariadne was the brains behind that particular operation. Theseus was just the muscle.

I'll be sure to thank the next spider I see.

-TG

[Army of GOD]

You're dumb if you don't have a couple rolls of string in case you need it. =P

What if your bulbs were cfl or led? Who's dumb now?

-TG

what if your light switches are digital?

[Symmetry]

Either works. I did like TG's string answer though. It's more interesting when people figure out their own solutions.

Theseus would be proud.

-TG

Ariadne was the brains behind that particular operation. Theseus was just the muscle.

I'll be sure to thank the next spider I see.

-TG

You're thinking of Arachne now.

[TA1LGUNN3R]

f*ck! I got 'em mixed up.

You're dumb if you don't have a couple rolls of string in case you need it. =P

What if your bulbs were cfl or led? Who's dumb now?

-TG

what if your light switches are digital?

Then I guess I'll have to build a complex Goldberg machine to push the switch.

-TG

[Symmetry]

Easily confused. Arachnophobia (fear of spiders) is derived from Arachne - the weaver who got turned into a spider (an arachnid) by Athena, plus Phobos (god of fear).

That's how I remember her.

[patches70]

You're dumb if you don't have a couple rolls of string in case you need it. =P

What if your bulbs were cfl or led? Who's dumb now?

-TG

Does not matter, the bulbs might not heat up but the sockets still do.

[WingCmdr Ginkapo]

Just install CCTV for christs sake.

Its not safe to go around touching hot bulbs.

[mrswdk]

TG's answer is dumb. what if you're on house arrest and can't buy long string?

Your answer is dumb. What if you have Congenital insensitivity to pain with anhidrosis (CIPA) and can't feel heat by touching a light bulb?

Insensitive jerk.

[Army of GOD]

TG's answer is dumb. what if you're on house arrest and can't buy long string?

Your answer is dumb. What if you have Congenital insensitivity to pain with anhidrosis (CIPA) and can't feel heat by touching a light bulb?

Insensitive jerk.

then you're a loser

[mrswdk]

your the one never heard of Amazon Prime buddy

[Army of GOD]

yes I have

that's how I got my Vanessa Hudgens fleshlight

[mrswdk]

Well if you've got a fleshlight then why are you wasting time working out which light switch to use? Now who's the loser?

[Army of GOD]

you still?

[2dimes]

The base of a cfl gets hot also. LEDs are the only ones that don't. Light switches are digital. They have two positions. I and O.