who can do this?!

[NixD]

How do you solve this puzzle? It's driving me nuts because I've done this sort of thing before but now I can't figure out for the live of me how I did it! I'm probably gonna kick myself when I find out, feel free to post the answer, though I'm really looking for the method on how to do it.
Cheers

Edit: For some reason the link isn't showing up for me in the post, if you click to quote the post you can get the link

Edit2: OK so that ones gone now too :/ use this - www. tburg.k12.ny.us /anderson/images/shape%20grid%20puzzle. gif (remove the spaces)

Or here's just the puzzle

[dangel]

Oh no i can't..

[SmileyUK]

its the puzzle to find the link, because even when quoting it isnt there

[NixD]

Ah crap, I put the link again with spaces

[dangel]

Hmm this is going to be a tough one to solve.

[dangel]

removed cos he fixed it

[NixD]

cheers, I'll add that to the original post

[kalniel]

Isn't it just a simple series of simultaneous equations?

You just express each shape in the terms of other shapes, so for example looking at squares (S) and triangles (T) and circles (C) you can get:

1) S+2T+2C =11
2) 2S+2C+T=16

Looking at 2) T=16-2S-2C, substitute this in 1 and you get
2C+3S=21

keep going and you get enough expressions to solve it?

[NixD]

Isn't it just a simple series of simultaneous equations?

Yeah that's how I tried solving it, I couldn't do it though :S

[SiM]

Put it into a matrix (have to add transposed matrix to the bottom for the vertical columns too) and do some row reduction... Its easy 1st year linear algebra... I can't be bothered to do it because of the stupid pictures... If you don't know the elementary row operations then look here

and don't try to solve it like a normal gcse simultaneous eqn, it will take you ages...

[TiG]

Its easy.



Key is find a change by one shape.

So 3Y + 1R + 1B = 17 and 2Y + 1R + 2B = 12

gives us 1Y - 1B = 5

Y = 5, B = 0

Then you get G = 3, R = 2 and missing value is 5

[kalniel]

Did you remember that some of the equations equal each other, for eg:

2Sq+2St+C = T+Sq+3St

and

2St+T+Sq+C = St+2Sq+2T

and don't try to solve it like a normal gcse simultaneous eqn, it will take you ages...

but it's more fun

[schmunk]

Answer whited out. I did it with simultaneous equations, and it took about 2 minutes, mainly to write the buggers down.
Triangle=0
Star=2
Square=5
Circle=3
?=5

[Blackmage]

yeh...worked it out already.easy

[SiM]

Well I suppose this one you can solve easily then... but, generally, in harder, big problems row reduction is the easiest way to do it quickly

[Steve B]

no matrix reductions needed:
consider column E and row 5, triangle and star are separated by 2.
Using rows 4 and 5, both triangle and star are even.
Considering column B, 17-3(square) must equal triangle plus star, which leaves only one value for both.
Work out the rest