Use the fact that rate equals work done over time, or $\displaystyle{r}=\frac{{W}}{{t}}\usepackage{cmbright}\Huge\$ . Henry's rate for the last job was $\displaystyle\frac{{400}}{{2}}\usepackage{cmbright}\Huge\$ square feet per hour. Find a fraction that expresses Henry's rate for the new job. These two fractions are equal.