[tex]\it 1+2+3+\ ...\ +25 = \dfrac{25\cdot26}{2} = 25\cdot13 = 325
\\ \\
1+2+2^2+2^3+2^4+2^5+2^6+2^7+2^8+2^9=
\\ \\
= 1+2+4+8+16+32+64+128+256+512 = 1023
[/tex]
Proporția devine:
[tex]\it \dfrac{325}{x} = \dfrac{\ \ 1023^{(1023}}{5115} \Rightarrow \dfrac{325}{x} =\dfrac{1}{5} \Rightarrow x = 325\cdot5[/tex]
