The hose will add 10 gallons after one minute, $\displaystyle{10}\cdot{2}={20}\usepackage{cmbright}\Huge\$ gallons after two minutes, $\displaystyle{10}\cdot{3}={30}\usepackage{cmbright}\Huge\$ gallons after three minutes, or $\displaystyle{10}{x}\usepackage{cmbright}\Huge\$ gallons after x minutes. Since the container already has 25 gallons in it, the total amount of water in the container will be $\displaystyle{y}={10}{x}+{25}\usepackage{cmbright}\Huge\$ after x minutes.