Manager gold

I paid 40% of my salary for gold dental floss, that is, twice as much as for fine catering. Hawaiian shirts cost me 1/6 and 10 percent of my salary went to jet fuel. I still have 400 euros left for coffee. How much did I earn as a manager?

Correct answer:

x =  3000 eur

Step-by-step explanation:

$$\begin{gathered} x-0.4x-\frac{1}{2}\cdot 0.4x-\frac{1}{6}\cdot x-0.1x=400 \\ x-0.4\cdot x-1/2\cdot 0.4\cdot x-1/6\cdot x-0.1\cdot x=400 \\ 0.8x=2400 \\ x=\frac{2400}{0.8}=3000 \\ x=3000=3000\text{eur} \end{gathered}$$

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