[tex]20\%=\frac{2\not0}{10\not0}=\frac{2\div2}{10\div2}=\frac{1}{5}\\\\10\%=\frac{1\not0}{10\not0}=\frac{1}{10}\\\\\\75-75\cdot\frac{1}{5}=75-\frac{75\cdot1}{5}=75-\frac{75}{5}=75-15=60\,\text{zl}\\\\60+60\cdot\frac{1}{10}=60+\frac{60\cdot1}{10}=60+\frac{6\not0}{1\not0}=60+6=\boxed{66\,\text{zl}}[/tex]
Obecna cena sprzedaży spodni wynosi 66 zł.
