Incorrect. The information leads to the equation $\displaystyle{x}{\left({20}-{x}\right)}={84}\usepackage{cmbright}\Huge\$ . This becomes $\displaystyle{20}{x}-{{x}}^{{2}}={84}\usepackage{cmbright}\Huge\$ or $\displaystyle{0}={{x}}^{{2}}-{20}{x}+{84}\usepackage{cmbright}\Huge\$ . Use the Quadratic Formula, and choose the smaller answer. The correct answer is 6.