Hi Anonymous,
$${\frac{{\mathtt{2.65}}}{{\mathtt{17.43}}}} = {\frac{{\mathtt{x}}}{{\mathtt{100}}}}$$ =>
x= $${\frac{{\mathtt{2.65}}{\mathtt{\,\times\,}}{\mathtt{100}}}{{\mathtt{17.43}}}} = {\mathtt{15.203\: \!671\: \!830\: \!177\: \!854\: \!3}}$$
2,65 € von 17,43 € => 15,2 %
Probe:
$${\mathtt{17.43}}{\mathtt{\,\times\,}}{\mathtt{15.203\: \!7}}\% = {\mathtt{2.650\: \!004\: \!91}}$$
Gruß radix ! (der sich über ein kurzes DANKE freuen würde.)