La Rubrica REZOLVATORILOR de PROBLEME , pagina 361, apare si numele meu (am subliniat) :TIMISOARA , Lic. industrial nr. 2 cl XI Ciobanu Petru (146)
In "2005 Tenure Test" , Problem II, point g) of the previous post, we have the very Sylvester Problem on page 323. It is exactly with the same demonstration. I took it from another source....(I don't know which one )
ANSWER CiP
The six cubes have sides of 1, 2, 3, 4, 5, and 6 meters respectively.
Solution CiP
If we denote by $a,\;b,\;c,\;d,\;e,\;f\;$ the dimensions (in meters) of the six cubes, then $1\leqslant a<b<c<d<e<f$ and
$a^3+b^3+c^3+d^3+e^3+f^3=441 \tag{1}$
But, since the cubes have unequal sides, it results :
$a\geqslant 1\;,\;b\geqslant 2\;,\;c\geqslant 3\;,\;d\geqslant 4\;,\;e\geqslant 5\;,\;f\geqslant 6 \tag{2}$
Then, the sum of their volumes $a^3+b^3+c^3+d^3+e^3+f^3$ is $\geqslant 1^3+2^3+3^3+4^3+5^3+6^3=1+8+27+64+125+216=441$
It means that in (2) we must have the equal sign everywhere.
$\blacksquare$

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