You mixed up the rate and the amount of water already in the container when writing the equation. The hose will add 10 gallons after one minute, $\displaystyle{10}\cdot{2}={20}\usepackage{cmbright}\Huge\$ gallons after two minutes, or $\displaystyle{10}\cdot{3}={30}\usepackage{cmbright}\Huge\$ gallons after three minutes. So the total amount of water is $\displaystyle{10}+{25}={35}\usepackage{cmbright}\Huge\$ gallons after one minute, $\displaystyle{20}+{25}={45}\usepackage{cmbright}\Huge\$ gallons after two minutes, or $\displaystyle{30}+{25}={55}\usepackage{cmbright}\Huge\$ gallons after three minutes. You need to find an equation that matches these numbers.