h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

My daughter's a sneaky so and so. If she's offered a sliced cake, she always takes the largest portion!

Now, if there are just two of you, the fairest way to divide a cake is that person A cuts, and person B chooses. Neither can complain that they got a smaller slice.

But how about if there are five of you, say?

How would they agree to divide a cake so that everybody was happy with their slice? No cake must be left over at the end.

Well, you could try using the * method;

_|_
/\

abit random, but I think you get the gist.

Or you could puree it in a blender and give everyone 100ml each. mmm, tasty.

I'm after the procedure, Matt. Who cuts (or blends/pours!), and who chooses? Everyone must be happy with their slice (drink).

oh.

hmm, apart from a complicated election procedure that could be a victim of tampering, not really sure.

Now look what you've done -

for

Well, you need to blindfold people: first one who cuts, then (s)he will be the last to get a slice. One after the other, everybody is blindfolded, and the plate is turned around by the others before a slice is taken by whoever's turn it is.

I don't think I'd be happy to accept a piece of cake I couldn't see, and hence couldn't judge against the others.

Cut the cake into ten pieces?

Blindfold the recipients?

Show them a film of the starving in Ethiopia/Sudan/Leeds so they're just grateful for anything they get?

Why? Who cuts, who chooses? I'm not saying that this is correct by the way (because it isn't).

Well if it isn't right, why should I waste my time explaining the complicated computational models used to analyse the available data and create an equitable, workable solution? That would just be a waste of time and pixels. Do you think I've got nothing better to do all day than sit typing here? Why, I could be off doing something far more interesting instead. Maybe I shall. Harrumph.

*picks at the icing*

Easy!

Get mum to slice it!..

My childhood memories are always of being given a smaller slice than my siblings were given, so I'm not allowing any higher authority like Mums, for example. The cake eaters must work it out for themselves.

Getting everyone to cut a piece for the person on their left? Would that help?

I'd cut a small piece for the person on my left!

Get everyone to cut a piece for the person on their right?

You greedy so-and-so!

Bel, I was illustrating a point of procedure, in that the proposed algorithm would not have met with unanimous approval.

Ok, you need a scale. Weigh the whole cake, divide by five. Cut one piece, weigh, add or substract unrtil it's exactly the weight you need. Do another three times - bingo.

Throw out the original cake, buy either a packet of Jaffa Cakes or some cake bars and distribute evenly.

Bel, I'm sure that most people would be happy with that, but I'm after another method which only requires a cake, a knife, and 5 greedy people.

One person is nominated the knife wielder. They then kill all the others and eat the whole cake themselves. Job sorted.