# Task 3. (3 points)

In the country of Taxia, everyone pays as many percent in taxes as thousands of tugriks their salary amounts to. What salary is the most advantageous to have?

(Salary is measured in a positive, not necessarily integer number of tugriks)
Answer: 50000 tugriks

Solution:

Let's denote the salary as $x$. Then what remains after the tax deduction is $x-\frac{x^{2}}{100000}$. This is a quadratic trinomial with a negative leading coefficient, it reaches its maximum at the vertex when $x=50000$.