IOM 2016, Блиц — Задача 71

Olympiad of Metropolises, Moscow. Blitz Contest, September, 5 · 5 септември 2016 г.

Условие

In a theatre, there are 20 rows of 14 seats each.

The tickets for the seats in the front $n$ rows cost $5/3$ the cost of the other tickets.

Yesterday the total income was $181.6$ times the cost of a seat in the front rows;

knowing that only 4 seats of the theatre remained unsold, calculate the value of $n$.

Решение

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Оригинал в Архива: blitz.pdf