A Crazy Riddle

You are in the downstairs lobby of a house. There are three switches. all in the “off” position. Upstairs, there is a room with a lighibulb that is turned off. One and only one of the three switches controls the bulb. You want to discover which switch controls the bulb, but you are only allowed to go upstairs once. How do you do it? (No fancy strings. telescopes, etc. allowed. You cannot see the upstairs room from downstairs. The lightbulb is a standard 100-watt bulb.)

#Riddles

Easy Math Editor

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`\sum_{i=1}^3`	$\sum_{i=1}^3$
`\sin \theta`	$\sin \theta$
`\boxed{123}`	$\boxed{123}$

Comments

You turn on the first switch and wait for 2 minutes, then turn it off. Then you turn on the 2nd switch and go upstairs. If the bulb is on it is controlled by the 2nd switch, if not then you touch it. If its hot its the 1st switch, if not then its the 3rd one. :-)

n. y. - 7 years, 6 months ago

Same thing holds good for three fans also!!

Vasavi GS - 7 years, 6 months ago

Google search of course.

A Former Brilliant Member - 7 years, 6 months ago

It is actually not possible to do with only one trip upstairs, but you can do something like what N. Y. said

Alex Pan - 7 years, 6 months ago

You tell someone to go in the room and yell across the house "IS IT ON!" and if they say no go to the next switch .😂

Takiera Mayo - 5 years, 10 months ago

turn all 3 switches on and go upstairs..

Troy Nicholson - 5 years, 7 months ago

Math	Appears as
Remember to wrap math in `\(` ... `\)` or `\[` ... `\]` to ensure proper formatting.
`2 \times 3`	$2 \times 3$
`2^{34}`	$2^{34}$
`a_{i-1}`	$a_{i-1}$
`\frac{2}{3}`	$\frac{2}{3}$
`\sqrt{2}`	$\sqrt{2}$
`\sum_{i=1}^3`	$\sum_{i=1}^3$
`\sin \theta`	$\sin \theta$
`\boxed{123}`	$\boxed{123}$