[tex]As\ is\ 120\%\ Bs\\\\120\%=1.2\to\frac{As}{Bs}=1.2\\\\\frac{As}{Bs}=\frac{12}{10}\to\frac{Bs}{As}=\frac{10}{12}\to\frac{Bs}{As}=\frac{5}{6}\\\\\frac{5}{6}\cdot100\%=\frac{500}{6}\%=83\frac{1}{3}\%\\\\100\%-83\frac{1}{3}\%=16\frac{2}{3}\%\\\\Answer:Bs\ income\ is\ 16\frac{2}{3}\%\ less\ than\ As\ income.[/tex]