Difference between revisions of "1996 OIM Problems/Problem 1"

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== Solution ==
 
== Solution ==
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A cube with edge <math>n</math> can be divided at the most into <math>n^3</math> cubes with side 1.  Since <math>12^3 < 1996 < 13^3</math> then smallest <math>n</math> cannot be less or equal to 12.  Now we need to find out if it is possible to divide a cube of edge 13 into 1996 cubes.
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Since <math>13^3-1996=201</math>, this means that I have 201 extra cubes of side 1.  Now we need to find out if we can if I can combine groups of these into other cubes of larger edge sides until my total of cubes is 1996.  That is, I can combine 8 cubes into a cube of edge 2, 27 cubes into a cube of edge 3, <math>k^3</math> cubes into a cube of edge <math>k</math> and so on...
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~Tomas Diaz. ~orders@tomasdiaz.com
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{{Alternate solutions}}
  
 
== See also ==
 
== See also ==
 
https://www.oma.org.ar/enunciados/ibe11.htm
 
https://www.oma.org.ar/enunciados/ibe11.htm

Revision as of 08:58, 23 December 2023

Problem

Let $n$ be a natural number. A cube with edge $n$ can be divided into 1996 cubes whose edges are also natural numbers. Determine the smallest possible value of $n$.

~translated into English by Tomas Diaz. ~orders@tomasdiaz.com

Solution

A cube with edge $n$ can be divided at the most into $n^3$ cubes with side 1. Since $12^3 < 1996 < 13^3$ then smallest $n$ cannot be less or equal to 12. Now we need to find out if it is possible to divide a cube of edge 13 into 1996 cubes.

Since $13^3-1996=201$, this means that I have 201 extra cubes of side 1. Now we need to find out if we can if I can combine groups of these into other cubes of larger edge sides until my total of cubes is 1996. That is, I can combine 8 cubes into a cube of edge 2, 27 cubes into a cube of edge 3, $k^3$ cubes into a cube of edge $k$ and so on...

~Tomas Diaz. ~orders@tomasdiaz.com

Alternate solutions are always welcome. If you have a different, elegant solution to this problem, please add it to this page.

See also

https://www.oma.org.ar/enunciados/ibe11.htm