Using your Head is Permitted

October 2011 riddle

This riddle has a long history. I'll give credit on the solution page.

In many post offices around the world, the price of sending a box-shaped parcel is a (monotone, non-decreasing) function of the sum of its dimensions: length+width+height.

  1. Is it (ever) possible to save money by placing your parcel inside a larger parcel?
  2. Is it (ever) possible to do the same, in a post-office that works the same way but ships out parcels that have more than 3 Euclidean dimensions?
Answer both questions with proof for credit.

List of solvers:

Wenqi Zhang (2 October 09:58)
Pei Wu (3 October 01:05)
Daniel Bitin (7 October 02:12)
Joseph DeVincentis (12 October 21:49)

Elegant and original solutions can be submitted to the puzzlemaster at Names of solvers will be posted on this page. Notify if you don't want your name to be mentioned.

The solution will be published at the end of the month.


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