# homework riddle

Found 7th Dec 2010
my 8 yr olds homework has left me stumped. can anyone help please.

there are three switches downstairs. each turns on one of the three light bulbs in the attic. you can turn the switches on and off and leave them in any position. how would you identify which switch turns on which light bulb, if you are only allowed one trip upstairs?

you can use pictures and words.

Groups
1. Misc

Turn on one switch and wait five minutes. Then turn that switch off and turn on another. Enter the room and touch the light bulb. Obviously, If the light is on the genuine switch is the second one. If the light bulb is off and cold it is the third one and if the light bulb is warm and off it is the first switch. If the light had been turned on for five minutes it would have warmed up.

Turn on two bulbs.

After 10 mins turn one of these off

Go to loft

One bulb is on - easy to identify with switch

Touch both the other bulbs

The hot one is the other switch you turned on.

i'd complain to the school for encouraging 8 year olds to touch lightbulbs.

Turn on one switch and wait five minutes. Then turn that switch off and … Turn on one switch and wait five minutes. Then turn that switch off and turn on another. Enter the room and touch the light bulb. Obviously, If the light is on the genuine switch is the second one. If the light bulb is off and cold it is the third one and if the light bulb is warm and off it is the first switch. If the light had been turned on for five minutes it would have warmed up.

How does this match all three bulbs to all three switches?

Edited by: "cannyscot" 7th Dec 2010

Turn switch A on for 1 minute then off again
Turn switch B on
Go upstairs

One light will be on- B
One light will still be warm - A
One will be cold - C

Banned

cannyscot

How does this match all three bulbs to all three switches?

are you serious or just thick?

^^ because the first switch is the hot bulb that is off, the second switch is the one lit and the third bulb is off and cold.

DangerGod

are you serious or just thick?

No, I'm serious, the answer is wrong.

.[/quote]How does this match all three bulbs to all three switches?Wrong answer I'm afraid.[/quote]

How can it be wrong, it's the same as yours but worded differently!!!

Banned

cannyscot

No, I'm serious, the answer is wrong.

No, its really not.

cannyscot

No, I'm serious, the answer is wrong.

its the same answer you gave, except he turns 1 on at a time instead
Edited by: "athunder" 7th Dec 2010

Original Poster

i didnt think of touching the bulb and hope thats not what they are encouraging our kids to do, but thanks for the replies. now at least we have something to hand in tomorrow!

don hedron

i didnt think of touching the bulb and hope thats not what they are … i didnt think of touching the bulb and hope thats not what they are encouraging our kids to do, but thanks for the replies. now at least we have something to hand in tomorrow!

lol...will you claim half the marks too?
Edited by: "greg_68" 7th Dec 2010

The pic will be 3 lightbubs, 1 on 2 off and a kid holding one screeming "OUCH"

Original Poster

The pic will be 3 lightbubs, 1 on 2 off and a kid holding one screeming … The pic will be 3 lightbubs, 1 on 2 off and a kid holding one screeming "OUCH"

tempting!

Original Poster

lol...will you claim half the marks too?
[/quote]
no, im gonna blame you lot!