Postal extortion

Surely many were taken aback when, after ordering and paying for goods from China, e.g. from ebay, a shipment goes from person A (seller) to person B (buyer) to Slovakia. You pay the value of the goods, postage, and newly also VAT. You wait two months, and the postwoman comes with the shipment and asks for another 3.50 euros as a fee for customs debt and other fees.

The task is: Calculate the percentage overpricing of a shipment, during delivery by post, if a shipment with postage and VAT has a value of 10 euros and the post adds another 3.50 euros as a self-assumed fee "for customs debt and other fees".

Final Answer:

p =  35 %

Step-by-step explanation:

$$\begin{gathered} a=10\text{eur} \\ b=3.5\text{eur} \\ p=100\cdot \frac{b}{a}=100\cdot \frac{3.5}{10}=35\% \end{gathered}$$

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