x ilosc banknotow o nominale 100 zl i jednoczesnie ilosc banknotow 50 zl
100x-wartosc banknotow 100 zl
50x-wartosc banknotow 50 zl
12000-wyplacona kwota
100x+50x-wyplacona kwota
100x + 50x =12000
150x =12000. / :150
x=80
x=80 banknotow o nominale 100 zl i 50 zl
80+80=160