Odpowiedź :
160zl-netto
172,80-brutto
100%-------->160
x%------------>172,80
160x=17280/160
x=108%
108%-100%=8%------------->opodatkowanie towaru
10%z 172,80=17,28
5%=8,64
17,28+8,64=25,92zl
172,80-25,92=146,88zl------->tyle trzeba zaplacic po obnizce o 15%