\section*{Problem 4 - 121014}

In an old textbook, a problem reports on the following trade:

A farmer wanted to buy several animals from a livestock dealer. The dealer demanded the same price for each animal. The farmer managed to negotiate this price down by exactly the same percentage of the demanded price as it was supposed to be (in groschen).

He now paid 21 groschen per animal. At the original price, his money would have been enough for exactly 3 animals. Now he could buy more animals, spending all his money.

How many animals could the farmer buy in total?