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$$\left(\begin{array}{c}R_1\\R_2\\R_3\end{array}\right)=\underbrace{\left(\begin{array}{c}3 & 3 & 6 & 7\\4 & 0 & 2 & 5\\5 & 8 & 1 & 0\end{array}\right)}_{={_R}M_Z}\cdot\underbrace{\left(\begin{array}{c}5 & 6\\2 & 0\\0 & 5\\3 & 4\end{array}\right)}_{{_Z}M_E}\cdot\binom{420}{750}$$$$\phantom{\left(\begin{array}{c}R_1\\R_2\\R_3\end{array}\right)}=\underbrace{\left(\begin{array}{c}42 & 76\\35 & 54\\41 & 35\end{array}\right)}_{={_R}M_E}\cdot\binom{420}{750}=\left(\begin{array}{c}74\,640\\55\,200\\43\,470\end{array}\right)$$$$K=\left(\begin{array}{c}74\,640\\55\,200\\43\,470\end{array}\right)\cdot\left(\begin{array}{c}25,00€\\51,00€\\37,50€\end{array}\right)=6\,311\,325,00€$$