You may have chosen this answer because all three values add up to 25. However, to be correct the values need to make each of the conditions true. Let $\displaystyle{x}=\usepackage{cmbright}\Huge\$ the smallest, $\displaystyle{y}=\usepackage{cmbright}\Huge\$ the middle, and $\displaystyle{z}=\usepackage{cmbright}\Huge\$ the largest number. The correct system with which to start is $\displaystyle{x}+{y}+{z}={25}\usepackage{cmbright}\Huge\$ , $\displaystyle{y}-{x}={1}\usepackage{cmbright}\Huge\$ , and $\displaystyle{2}{y}-{z}={2}\usepackage{cmbright}\Huge\$ .