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2day's IQ Test: The Switches and Light Bulbs

May 12th, 2008        
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An IQ test here for you all – John is in a big mansion and he needs to match out the three switches located on the top floor for the three light bulbs located at the ground floor (not visible from top floor) but he can only get down once to check out the bulbs. No other devices were used, only hands.

More details:
There are 3 switches on the top floor – switch A, switch B and switch C and they were used to switch on the 3 light bulbs located at the ground floor. John needs to find out the switch for each of the bulbs but he can only get to the ground floor once to check the bulbs.

- Nothing tricky.
- Nothing to do with the wiring.
- John is alone in the mansion.
- No other devices were used for the checking.
- The switches are normal type which can only be on/off.

The question is ~ How John managed to know which switch goes to which light bulb by getting down once only. It is a test from a friend. Do you guys know the answer? Comment please.

Update: Wow! That’s cool! Someone has already got the answer in the comments, let’s make it more fun, so post your answer before checking out the comments.

Author:
 
  • http://www.gadgetindo.com DmZ

    Swith on A after 10 minutes swith on B and then go to the ground floor to check the bulb. Touch the light bulb that light on, the hotest bulb is switch A, other is switch B, the bulb witch light off is switch C.

  • http://ovidel46.saltwaterc.net Ovidel

    Simple…
    There is switch A B and C. Light bulb 1 2 and 3. First he switches each one to see which one is brighter. – The brighter is light bulb no 3 (let’s say with switch B).
    Then there are A and C – he switches one on and sees which one is which.

  • http://www.2dayblog.com webmaster

    the lighting is not visible from the top floor,
    DMZ got the right answer. How long it takes for you to figure that out? I gave up for this test actually hahaha

  • http://emmade.blogspot.com Chica

    john can switch on all de bulbs while scaling down de stairs he can make marks on de wiring, once he reach de landing he will folow whc wires that goes to wch bulbs. or easy…..he jus call out someone to be in de other floor. n check out wch bulb is lighting up wen he flick.TADAAAAA!!

  • http://www.2dayblog.com webmaster

    John is alone in the mansion.

  • http://www.gadgetindo.com DmZ

    @webmaster: it just pops out in my mind, any price for the right answer? ehehehe..

  • http://www.2dayblog.com webmaster

    no prize for you DmZ, it’s an IQ test, hahahaha.

  • isura

    bad engineering.. who would put the switches for the bulbs on one floor and the bulbs themselves on another?

  • http://www.2dayblog.com webmaster

    hahaha, it’s just an IQ test buddy

  • isura

    to webmaster: sorry.. just kidding though

  • winterlove

    so..what’s the answer? and who is the right one?

  • http://www.2dayblog.com webmaster

    the first comment is the answer, by dmz. Switch on one bulb (A) for 5 minutes , after that off it, then quickly switch on one more bulb (B) and left one off (C). So when you get to the ground floor, touch it, the hottest one should be (A) cuz it has been switched on for 5 minutes then off, and secondly the one that is switched on should be (B) and the one which is off will be (C). Cool right. lol.

  • Pinky and the Brain

    Here is the real answer and you don’t have to wait 5 or 10 minutes. First turn on 2 two light switch on for 20 seconds. Then you turn one light switch off, leaving the other switch on. After that you go down to the lights. The light that is on is the switch that is on, the light that is warm by the touch is the light you just turned off, and the light that is cool is the switch which you didn’t turn on.

  • Danielle Morrison

    The light bulbs are three different colour, and when he turns each one on in the dark mansion, the mansion will light up a different colour… he leaves the lights on then goes down stairs, remembering what colour the mansion glows for each switch! he then knows the answer! lol i hope im right

  • http://www.2dayblog.com webmaster

    To Pinky and the Brain: that another similar answer, great!

    To Danielle Morrison: erm, that is not right, because he can only get down once.

  • Angela_babewen

    put a mirror under the stair to see

  • Js_hew

    Take out one bulb

  • Vipin_mathew1

    first of all he has to turn on one switch for a long time and switch off that,meanwhile turn on immediately the second switch and go upstairs for seeing the glowing bulb, also he can understand the first switch by touching the two non-glowing bulbs in which the bulb for the first switch will be hot because of working for a long time before….then the third bulb can also be identified

  • Glenn Todd

    you leave on 1 switch, you leave off 1 switch and you turn on 1 switch for just 10 seconds, 1 bulb will be hot, 1 bulb will be warm & 1 bulb will be cold