The total rainfall for the summer of 2009 was $\displaystyle{1.5}+{2.5}+{1.5}+{3}={8.5}\usepackage{cmbright}\Huge\$ and the total rainfall for the summer of 2010 was $\displaystyle{2}+{2}+{3.5}+{3}={10.5}\usepackage{cmbright}\Huge\$ . The total rainfall for both summers is $\displaystyle{10.5}+{8.5}={19}\usepackage{cmbright}\Huge\$ .