Log in

No account? Create an account
Brainteaser answer - 'Twas brillig, and the slithy toves did gyre and gimble in the wabe [entries|archive|friends|userinfo]

[ website | Beware the Jabberwock... ]
[ deviantArt | the-boggyb ]
[ FanFiction | Torkell ]
[ Tumblr | torkellr ]

[Random links| BBC news | Vulture Central | Slashdot | Dangerous Prototypes | LWN | Raspberry Pi]
[Fellow blogs| a Half Empty Glass | the Broken Cube | The Music Jungle | Please remove your feet | A letter from home]
[Other haunts| Un4seen Developments | Jazz 2 Online | EmuTalk.net | Feng's shui]

Brainteaser answer [Tuesday 2nd November 2010 at 8:09 pm]

[Playing |Canon ~ Pachelbel/Classical Chillout Gold - Disc 5]

Several people came up with solutions to yesterday's puzzle that only required moving one matchstick, but only one person found the real answer. For reference, the equation was this:

I + XI = X

And the challenge was to work out what the fewest numbers of moves was required to make a valid equation.

delta_mike spotted the obvious solution of moving the second I to the far right, giving I + X = XI (this is the one I tried originally). talismancer came up with a slight variation on this as well.

Bonus marks to omgimsuchadork for the inventive answer of moving the I to create I + XI ≠ X

One guy at work found yet another 1-move solution: I - XI = -X

Of course, this is a trick question and so none of those are correct. The correct answer is none, and bragging rights to the_s_guy for spotting that.

The solution is to rotate the surface your matchsticks are on (or walk round to the other side of the table), giving X = IX + I which is 10 = 9 + 1 and so is correct.

I actually didn't solve this by working that out - I saw that I could do it with 1 move, mistakenly assumed that it wasn't a trick question (I should have known better by then), and so entered 1 as my answer. When the game rejected it I then entered 0, as if it takes less than 1 move then there's only one possible answer left.
Link | Previous Entry | Share | Next Entry[ Penny for your thoughts? ]