[tex]\frac{48}{120}=\frac{x}{100}\ \ \ \ \ |\frac{48}{120}=\frac{48:6}{120:6}=\frac{8}{40}=\frac{8:4}{20:4}=\frac{2}{5}\\\\\frac{2}{5}=\frac{x}{100}\ \ \ \ |cross\ multiply\\\\5(x)=2(100)\\\\5x=200\ \ \ \ |divide\ both\ sdies\ by\ 5\\\\\boxed{x=40}[/tex]