[tex]We\: a\: system\: of\: equations:\\\begin{cases}A+B+C=52000\\A-B-C=0\\30A+24B+18C=1336800\end{cases} \\ \Leftrightarrow \begin{cases} A=26000\\B=14800\\C=11200\end{cases} \\ There\: are\: 26000\: seats\: in\: section\: A, 14800\: seats\: in\: section\: B,11200\: seats\: in\: section\: C.
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